The Whole Nine Yards (2000)

In Montreal, Canada, down-on-his luck dentist, "Oz" Oseransky (Matthew Perry), discovers that his new neighbor is Jimmy "The Tulip" Tudeski (Bruce Willis), former mob-contract-killer-turned-police-informant upon whose head the Hungarian mob has put a steep price. Egged on by his loathsome wife Sophie (Rosanna Arquette), Oz sets off to Chicago to let the mob know where The Tulip is--and hopefully claim part of the reward.