Kiss Kiss (Bang Bang) (2001)

Felix is a hit-man who wants out of the business. He takes up a job to look after a reclusive man named Bubba who is like a giant kid, he doesn't understand people and doesn't know much, never having seen the outside world before. But Felix has bigger problems. He wants to patch up his relationship with his ex-girlfriend, and he's being targeted by his old colleagues who are not letting him get away from his past so easily.