Remember dating? Remember when it used to be fun? Remember when it wasn't hell on earth? If you look at your little address book with the feeling that it is not a force for good, then "Cross My Heart" will not make you feel better. The movie, which stars Martin Short and Annette O'Toole, is the closest thing on record to an account of the worst date ever. And, as such, it provides a useful social function: It gives us the complete lowdown on the horrors of the dating life.

This anatomy of a bad date starts with the usual pre-date ablutions, and a sketch of the details may sound very familiar, but no, this is not a documentary. Martin Short is David, a sunglasses salesman who makes a date with Kathy (Annette O'Toole) to celebrate his new promotion. Kathy and David have gone out together twice before and they like each other in the way that people like each other after only two dates and think that they've found "the one." Neither party is new to this game, but they throw themselves into their preparations for their night together with awe-inspiring vigor and optimism.

However, there are problems even before the date begins. Instead of getting a promotion, David loses his job and is afraid that if he tells Kathy, she'll think he's a loser and head for the hills. Also, he's not exactly frank about a couple of other little things, like the car he's driving and the apartment he's taken her to, both of which belong to his best friend Bruce (Paul Reiser).

Kathy has fudged on a few pertinent facts as well, the most prominent being the existence of her 7-year-old daughter. But instead of dampening the evening, the lying only serves to stoke the sexual subtext; it ups the ante.

For about the first 30 minutes of "Cross My Heart," the hopes and fears, and the elaborate self-evaluations and self-rationalizations of the couple carry you right inside their spinning heads. The scenes focusing on their pre-date anxiety are hilariously authentic; in their desperation to make a good impression, they drive themselves into a kind of precoital panic -- trying on one outfit after another, shaving, spraying, teasing, plucking, checking their suavity in the mirror -- until it's a miracle that either has the energy to walk out the door.

The director, Armyan Bernstein, who, along with Gail Parent, also wrote the script, is in complete control of these giddy early scenes, so that practically every line pays off. The movie is really a long, scripted improvisation for two on the travails of modern romance, and the actors perform an engaging comic pas de deux.

Short and O'Toole pair up nicely: They look like they'd be attracted to each other. With her pointy nose, blue eyes and flame-red hair, O'Toole has smashingly average good looks; she's an everyday kind of beauty, and the hint of maternal voluptuousness she brings to the role softens Short's geekiness.

O'Toole plays Kathy as a woman who knows intellectually that's it not in her best interest to sleep around, but can't quite get her body to agree. Her performance is shrewdly physical, and there's great skill in the way she conveys the back-and-forth motion of Kathy's feelings.

With all his elfin exuberance, Short's physicality is much broader but no less skillful. The fact that David is hiding something, and at any moment is about to be found out, manifests itself in every fiber of Short's body. And as the night progresses, and his lies become increasingly baroque, a hunted look spreads over his face. When the worst happens, he's ready for it.

And eventually it happens and both participants are unmasked for the lying cads they are. The point, though, is that neither of these people is a bad egg; down deep, they're sweet, decent, likable folks, and this is what the awful pressures of dating have driven them to.

At first, this satire on sexual manners is sharp and winning. And even when the dialogue flattens, you skate along on the charm of the actors. But about midway though, the movie loses inspiration. Once the couple gets into bed, the movie becomes a routine sex comedy with the customary jokes about the awkwardness of sex with a stranger. To give the material a contemporary slant, there's a condom scene, and the filmmakers may feel that they're on the cutting edge with this safe sex message. And they are, I suppose, but in that no-cost, Hollywood manner. "Cross My Heart" falls right in step with "Fatal Attraction," "No Way Out" and other recent movies in suggesting that a casual night on the town is the risk equivalent of juggling napalm. There is a happy ending and a happy message: Be yourself. And surely that's a sentiment we can all get behind. Yes, that's nice. Be Yourself! Very nice ... Check! Cross My Heart, at area theaters, is rated R and contains some nudity, sexual situations and adult language.