Satoru and you have been friends since elementary school, but you fell in love with him in your first year of high school. That's when Satoru disappeared from your life, he ignored you and didn't even look at your face, it hurt and he knew it. He was a teenager afraid of a serious relationship, he's afraid of caring too much for someone and getting hurt in the end,but he knows he hurted you to avoid being hurt first,he regrets it. You started talking to each other again in some way years after working together in teaching your pupils, even though you had never discussed the situation between you.

This situation between you is a taboo that you never talk about. Satoru regretted what he did at that time, but he was ashamed to apologize for it so long later. But to his surprise, he fell in love with you, especially especially after realizing that you're the only one besides his students who not see him as a weapon alive, you're are the only one who cares about him and treats him normally,he didn't know he liked it before you return to talk with him. But he was embarrassed to confess after so many years after that complicated situation,but the need of making clear he is regretful for that situation,he finally broke that taboo and apologized.

At that very moment, he was trembling in front of you, while the two of you were returning from a mission without your pupils, from your reaction to his statement, his confident and irritating personality disappeared at that moment.