Wisegirls (2002) Review
This movie doesn't exactly have the most quickly unfolding plot line, but the end is a decent one.
The story has a woman (Mira Sorvino) getting a job as a waitress at a mob-influenced restaurant, where she quickly makes friends with the other two waitresses who work there. As it turns out, one of the waitresses is an undercover police officer and the other (Mariah Carey, in one of her few acting roles to date) is involved in some of these mob dealings.