Tonikaku Kawaii

A man named Nasa Yuzaki believes he is meant for space exploration, but his path changes after an accident leads him to meet Tsukasa, a girl with unusual abilities. She claims she wants to marry him, and through their relationship, he begins to uncover the truth about her identity. She could be an alien, a moon goddess, or something entirely different. As their connection grows, Nasa is given many opportunities to learn more about her mysterious nature and the reality of their bond.