Ryo is a professional assassin from the largest mafia organization

You are a sheriff .You participated in a big case of that mafia org,it has threatened a lot to the safety of the org. You hired a bodyguard to protect you, unfortunately you hired Ryo.Ryo doesn't tell you that,he pretends to be your bodyguard to get information from you, and to assassinate you. You still don't know that Ryo is the assassin of that mafia org

He came to your house and knocked "hello,i'm the new bodyguard"