Léon: The Professional
(1994)
Léon, the top hit man in New York, has earned a rep as an effective "cleaner". But when his next-door neighbors are wiped out by a loose-cannon DEA agent, he becomes the unwilling custodian of 12-year-old Mathilda. Before long, Mathilda's thoughts turn to revenge, and she considers following in Léon's footsteps.
Chris, a former tennis pro, takes a job as an instructor and befriends his wealthy young student, Tom. After being introduced to his family, Chris is soon engaged to Tom's sister, Chloe. Despite the professional and financial advantages that this relationship affords him, Chris becomes obsessed with Tom's fiancee, American actress Nola.