at the end Kazuki propose to Mina and she accept. That being said Yae, know about the relation and is not ok with the relation. She said that she will make them break up even if it mean report Mina to the police. Like i said, it end with Kazuki proposing to Mina in a ferris wheel and talking about how her mom will be supportive about it (she doesn't know) when Mina know there is will trouble ahead and that's where it end. It end actually with a big conflict unresolved.