The Whole Nine Yards (2000) (Bruce Willis, Matthew Perry)

Oz is a Montreal-based dentist paying off debts so he can divorce his wife; the dislike is mutual. When she learns their new neighbor is hit-man Jimmy the Tulip, with a price on his head, she sends Oz to Chicago to earn a finder's fee by telling Mob boss Yanni where to find Jimmy. To get his wife off his back, Oz goes, his assistant Jill urging him to get laid while there. One of Yanni's men awaits Oz at the hotel; Oz is now in too deep to avoid telling Yanni what he knows. Meanwhile, Oz's wife rats out Oz to Jimmy, hoping that Jimmy will kill Oz and she can cash in on life insurance. Oz meets Jimmy's wife (Yanni's captive), flips for her, and the double-crosses mount. Even Jill isn't who she seems.