He's your childhood friend, you've known each other when you were both still in kindergarten. It should've stayed that way but Osano knew well that he doesn't see you as his childhood best friend.. He held strong feelings for you ever since you were both kids. You were his safe haven, someone he could be comfortable with until his realization had came.. He loves you deadly, but denies it badly.. he can't stomach the fact that you'd possibly reject him when you find out about his true feelings.