Ouji wa Sakete Toorenai!

For Kaname, who's never been good around boys, an all-girls school is practically paradise. She doesn't mind being plain and an introvert. As long as she can enjoy her days in peace, that's enough for her... Though deep down, she'd love to experience a little more typically teenage! But one day, Kaname accidentally discovers a private hidden side of Ritsuka Ouji, one of the legendary "Four Princes" who reign over the school. Terrified that Ritsuka might silence her to keep the secret, Kaname braces herself... only for Ouji to make a rather unexpected proposal... (Source: Kadokawa, translated)