Onegai Teacher

In this sci-fi romantic comedy, An alien is ordered to investigate earth, making sure that it's teachers are doing well, so she becomes a teacher herself. When she shows up, however, she is seen by one of the students, and must keep him quiet. He escapes into her ship and is transported to another realm, and she has to keep him from being erased. In the mean time, she begins to fall in Love with him, and due to a misunderstanding, they are forced to get married. Now, they must keep her identity and their marriage a secret, and try to live out normal lives.