A Budding Maiden's Heart is the thirteenth chapter of the Oushitsu Kyoushi Heine manga.
Beatrix von Lothringen, Kai's fiancee who's often mistaken for a young man due to her habit of dressing in men's clothes, has come to visit the palace. She proposed to Kai that they go on a picnic together because she secretly wants to start acting like a real couple, and Kai agrees, but also brings along everyone else. At the picnic, Beatrix's various attempts at showing Kai her feminine side, such as feeding him lunch that she made herself or having him give her a flower crown, fail. When the picnic is rained on, they are forced to go back to the palace, where Beatrix changes into a frilly dress, embarrassing her. However, when she's about to leave, Kai appears and gives her a flower crown, telling her that it goes with her dress. This cheers her up, and she tells everyone that they should do this again some time.