How would a guy react if he finds out the girl that hated him during childhood always liked/loved him?

While it was exactly bullying, I was simply not friendly, gave him an attitude and sometimes made excuses to criticize his clothes or hair. I pretended to exclude him once from a research project. This went on from ages 9-13.

He asked me once ''why are you so angry, why you hate you''? I replied with an ''Shut up idiot. Does it look like I want to speak with you?''. In my private moments without anyone looking, I used to smile.

Eventually I grew out of that phase and we're going to be in our last year of HS after summer ends. We're friends now but I accidentally left my private journal at his house not so long ago and he returned it the next day. For sure he read it all or some of it. Guys how would you react if the girl you thought hated you... actually always had a crush on you?
Updates
1 y
The thing is he had a smile when he returned my journal. Now I can't hide the secret anymore.
How would a guy react if he finds out the girl that hated him during childhood always liked/loved him?
Post Opinion