While other working stiffs on the subway riffle through their tabloid newspapers in the instantly discardable romantic comedy Maid in Manhattan, Marisa Ventura (Jennifer Lopez) pores over Alice Miller's cult-fave psychological treatise ''The Drama of the Gifted Child.'' Although the Bronx-bred single mother and domestic engineer of the film's title, who cleans rooms at a Waldorf-esque hotel, is stuck in the same working-stiff income bracket, this graceless variation on ''Pretty Woman'' and ''Working Girl'' cannot emphasize thumpingly enough that in America, lowborn circumstances are no impediment to bettering oneself -- and, simultaneously, to bagging a prince. Especially if one is Jennifer Lopez.

There's an oversize Cinderella-slipper problem here, though, and it belongs to the prince. Or, more specifically, to a wan and watery Ralph Fiennes, desperately miscast as a supposedly dashing Senate candidate who doesn't realize that the couture-clad pretty woman who dazzles him at first sight is a maid. She is, after all, momentarily disguised: Egged on by a spunkier coworker, the usually faultless Marisa is illicitly togged out in selections from the closet of an obnoxious, rich guest (played with gusto by Natasha Richardson, with an assist from an antic Amy Sedaris as another wealthy hotel visitor).

That a highborn hero could fall for such a foxy heroine is understandable: Yo, she's J. Lo, keeping it real with the fans (in a steely, manufactured way) by wearing a drab hotel uniform in solidarity with less glamorous actresses. And that Fiennes would want to round out his résumé, post-''Red Dragon,'' by playing a character who isn't a twisted creep is also understandable -- at least on the part of the actor's agent. But no maid, and no fancy lady either, would swoon for a fellow as damp as the hero so grudgingly coughed up by Fiennes. In the words of Cinderellas everywhere, no effin' way.