What is the story in the credits???

arvin_1219 said:
Hina was crying because she told Kotarou that she likes someone for a long time (this is referring to Ayase Koyuki). Maybe Hina remembered her Senpai.

or maybe she was crying because she told Kotarou (what I said at the top) that hurt him.

Before the crying, Kotarou asked if Hina has someone she likes.

Famegher said:
At the end Kotaro and Hina end up together, so I believe her started to realize something about her feelings for Kotaro. So, the one she says she like from a long time is probably Kotaro and then she cried because she does not understand well their feelings yet.
The song say “he’s my hero” referring to Kotaro so I ended up thinking this way and I think it’s pretty good.