The Proposal (2001)

Terry Martin is the false name of an undercover cop posing as a fence to burrow into a gang run by Simon Bacig. After six months, Terry is closing in when Simon invites him to a party and tells him to bring his wife. His boss assigns him a rookie cop, Susan Reece, fresh from a data job in Kansas City. Terry wants her in and out the same night, but she wants a permanent assignment so she contrives to get Simon's attention. Terry must now pretend to live with her. Within a few days, the FBI warns Terry that Simon may have an informant within the police department, Terry discovers he really likes Susan, and he learns that she already knows Simon. Who's in danger from whom?