EROS IS a great mystery. The passions it unleashes sometimes push good people over the brink and destroy otherwise well-ordered lives. When it's over, we may not be able to make sense of what happened. Such is the stuff of which exciting comedy and drama are made. Several of this fall's movie romances bravely tackle this subject. However, by and large, they confuse their characters' good intentions with virtue, glossing over the hard questions.

The Mirror Has Two Faces is a conventional Hollywood star-vehicle, directed by the headliner herself, Barbra Streisand. Gregory Larkin (Jeff Bridges), an unmarried math professor at Columbia University, is unhinged by a string of unsatisfactory love affairs that have slowed the progress of his scholarly work and destroyed his peace of mind. He decides that the only way a man and woman can stay together is if they give up sex, and he places a personal ad in a newspaper for a celibate relationship-"looks unimportant.”

Rose Morgan (Streisand) is an unmarried professor of literature, also at Columbia, who lives at home with her aging beauty of a mother, Hannah (Lauren Bacall). She feels so unattractive she's scared to go out on a date. Her pretty older sister, Claire (Mimi Rogers), who has a history of stealing her boyfriends, answers Gregory's ad in Rose's name, and soon the two frumpy academics are enjoying each other's company.

After an intellectually satisfying courtship, Rose and Gregory get married. Forty years ago, the movie would have ended here with everyone living happily ever after. But this is the 1990s and fear of sex is almost as grave a sin as infidelity. Gregory wants their relationship to continue to be celibate, but Rose's libido cannot be quieted. So she leaves him.

Up until this point the movie seems to have a pro-ugly-duckling bias. Every good-looking man or woman turns out to be a rat, and those rated unattractive, like Rose and Gregory, all have hearts of gold. But while Gregory is pining away during their separation, Rose becomes one of the enemy. She has a complete physical make-over, emerging as the kind of glamorous beauty no man can resist, including her husband. All she has to do is throw her newly acquired good looks in Gregory's face, and he comes crawling back to her on her terms.

Adapted by Richard La Gravenese (The Fisher King) from a 1958 French film, the story is an uneven hybrid of a 1950s romantic comedy and a contemporary feminist fantasy in which women get even with insensitive males who are out of touch with their feelings.

Leaving aside the fact that neither Streisand nor Bridges are believable as ugly ducklings, the movie also fails to come to grips with the deeper implications of its subject matter. The initial hunger of Rose and Gregory for a celibate relationship suggests a critique of the so-called sexual revolution and its courtship rituals that the filmmakers are unwilling to undertake. Rose's switch from frump to beauty at the end seems more motivated by Streisand's own personal psychodrama than the dramatic development of the character. The actress-director has never made any secret of her own insecurities about her looks, and The Mirror Has Two Faces lays bare her conflicted feelings about her situation. Sometimes the superstar sees herself as an ugly duckling with a pure heart, other times as a killer vamp with men eating out of the palm of her hand. Her acting out of these contradictions in the film is interesting as therapy but flawed as entertainment.

Danish filmmaker Lars von Trier goes Streisand one better. He is obsessed with sex and religion. His latest movie, Breaking the Waves (winner of the Cannes Film Festival's Jury Prize), is a hodgepodge of both fixations with plenty of erotic thrills along the way.

Bess (Emily Watson) is an emotionally unstable woman who lives on a remote island off the coast of Scotland. She is a member of a fundamentalist Protestant sect that emphasizes God's judgment and wrath more than his mercy. The Church elders oppose her marriage to Jan (Stellan Skarsgard), an earthy, good-natured outsider who works on an off-shore oil rig nearby. The two tie the knot anyway and enjoy such a healthy sexual relationship on their honeymoon that Bess is devastated when Jan has to leave her to return to work.

The young bride is presented as a simple woman of faith, talking with God freely and often. During these conversations, she plays both parts, asking her questions out loud and then responding in God's voice, a more authoritative and lower-register version of her own. His answers aren't particularly insightful or wise. They seem to emanate more from her own harshly judgmental superego than a truly divine source. In one exchange, Bess laments Jan's absence and begs that he be sent back to her. As if in answer to her prayers, her husband is soon thereafter injured in an accident on the rig and returns to her completely paralyzed. Because of her petition, she believes it's her fault.

Jan's condition looks hopeless. Suicidal and depressed, he asks Bess to take lovers and tell him about the trysts. Those vicarious pleasures, he reasons, will keep him connected to life. Bess, who was a virgin before marriage, initially refuses. But when Jan's health worsens, her guilt button is pressed, and she agrees to act out his fantasies. Of course, she consults the Almighty, who is at first silent and then non-committal. He does, however, compare her to Mary Magdalene.

Bess does not enjoy her sexual escapades. They are masochistic experiences. But after each encounter, Jan gets better. Eventually she realizes she no longer has to recount her adventures to him for their magic to work. It seems her perverse version of self-sacrificing love, in and of itself, is keeping him alive.

Bess's conduct doesn't pass unnoticed. Her mother and the Church elders turn against her, denying her comfort and counsel, in a decidedly un-Christian fashion, when she needs it most. The island youth, also members of the sect, take to stoning her.

Bess finally martyrs herself in a grand gesture of sexual self-debasement, and Jan is miraculously cured. The movie's message seems to be that sexual humiliation can be a path to saintliness, and that organized religions, like the fundamentalist sect at hand, are an obstacle to sanctity.

Von Trier believes in the value of the purely spiritual experience which he means Bess's behavior to exemplify. He realizes that both religious faith and intense sexual desire can induce feelings of ecstasy. But he also resents the fact that Christianity presents us with a moral and ethical framework by which these experiences must be tempered. Rather than explore these issues, Breaking the Waves settles for a few sensationalistic shocks.

Like von Trier's film, The English Patient is also a profane work. But its superheated romance unfolds with great beauty. Its lovers defy most of society's accepted norms with an honesty and grandeur that makes their plight emotionally involving-even when their choices are morally disreputable.

An amnesiac, massive burn victim (Ralph Fiennes), whom no one can identify, is convalescing in an abandoned Italian monastery at the end of World War II. Hana (Juliette Binoche), a Canadian nurse, devotedly tends him. An East Indian bomb disposal expert named Kip (Naveen Andrews) sets up a tent in the courtyard and attaches himself to Hana.

This friendly trio is disrupted by an embittered allied intelligence operative calling himself Caravaggio (Willem Dafoe), who had his thumbs cut off by the Nazis. He claims to recognize the bed-ridden patient and moves into the monastery to find a way to get revenge.

As Hana reads to the burn victim from his journal, the dying man remembers the doomed love affair which led to his disfigurement. It seems the patient isn't English at all but a Hungarian count named Laszlo de Almasy who was once part of a pre-World War II band of geographer-explorers who nicknamed themselves “the International Sand Club.”

British writer-director Anthony Minghella (Truly, Madly, Deeply) has adapted the film from Michael Ondaatje's novel, and the action smoothly flashes back and forth between Laszlo's romantic desert adventures and the relationships that are emerging in the monastery.

The young Laszlo falls deeply in love with Catharine Clifton (Kristin Scott Thomas), the wife of a British colleague. Their secret, forbidden affair blossoms against the desolate background of the Libyan desert, with inter-ludes in Cairo dance halls and British army barracks. Through a convoluted series of circumstances, the two lovers are left stranded on the sand dunes as World War II begins. As she is too sick to travel, he leaves her in a cave covered with prehistoric paintings and searches for help. The British army mistakes him for a Nazi spy and takes him prisoner. He escapes and sells the International Sand Club's maps to the Germans in exchange for the means to rescue Catharine. But by the time he returns, she has died. He is shot down in a plane on his way back to Cairo and burned beyond recognition.

The Nazis used Laszlo's maps to facilitate their capture of Tobruk where Caravaggio was jailed and tortured as a spy. But the ex-POWis moved as he learns about Laszlo's tragic love story and forgives the man he once wanted to murder.

Minghella obviously intends the movie audience to do the same. However, when Hana helps Laszlo kill himself with an overdose of morphine, the flaws in the film's moral vision become apparent. The English Patient assumes that true love justifies almost anything. Laszlo and Catharine's grand passion is used to excuse infidelity, treason and assisted suicide. But it just won't wash.

A great romance can be the defining moment of a person's life. But its seductive fever doesn't exempt those involved from the moral consequence of the actions that follow. It's the conflict between these two forces that makes for great drama. If these three movies can be taken as evidence, today's filmmakers are reluctant to admit this.

John Prizer is based in Los Angeles.