Through a fluke, a maid at a ritzy Manhattan hotel (Jennifer Lopez) is mistaken for a guest by a guest (Ralph Fiennes) who's running for the Senate. This version of the Cinderella story was originally offered to Julia Roberts, implying that a Pretty Woman redux was intended, but what makes this comedy so appealing is that, unlike the 1990 Disney celebration of prostitution and patriarchy, it manages to infuse a fairy-tale fantasy with a healthy dose of reality--about not only what a maid's life and milieu are like but also the inner workings of a big hotel. There's an unusual number of genuine characters (as opposed to types) in the story--a credit to the script (Kevin Wade, working from a draft by John Hughes), direction (Wayne Wang), and high-energy cast, which also includes Natasha Richardson, Stanley Tucci, Tyler Garcia Posey (as the maid's unstereotypical and supportive son), Marissa Matrone (who plays a very rough approximation of the fairy godmother), Frances Conroy, Chris Eigeman, and an especially astute Bob Hoskins. Despite a continuity problem or two, this is one of those rare contemporary romantic comedies that actually work. 105 min. Century 12 and CineArts 6, Crown Village 18, Ford City, Gardens 7-13, Lincoln Village, Norridge, North Riverside, River East 21, Webster Place.