Completed - no set rel Manga

The general plot of the story is that a boy (yes, "he" is a boy) saved a man from outer space and the man turned the boy into a girl by using some kind of alien technology/potion and force "her" to be his wife. Who's the boy? He's a normal high school student who looks like a girl and is liked by his brother. Who's the man? He's the prince of one of the most powerful empires in the universe.

The story starts with a seemingly unassuming class rep Adachi Hana who has taken an interest in the school's known delinquent, Shinagawa Daichi. Just what is her reason for following Daichi and wanting him to go on the class field trip?