Kimi wa Meido-sama. GoGoAnime

Hitoyoshi, a high school boy living alone, hears a knock on his door. He opens it to find a strange girl offering to be his maid. She had beautiful dark hair, good manners, and… a dark past as a murderer. But despite her deadly background and lack of domestic skills, Hitoyoshi takes her in. As he adjusts to his new life, he begins to experience emotions he’s never experienced before.