The Protector(1999)

A mercenary's wife is killed while he was on a mission, so he gives up that life to help those who feel that their lives might be in danger. Currently, he is protecting a woman whose boyfriend's not only a mobster but a wacko, who goes berserk whenever he sees her with another man. One day, while having lunch with a male friend, the boyfriend kills him, so now she has to turn to this mysterious stranger to protect her.