Having a crush on my best friend

I never thought I'd like someone I've known for a long time cos usually I'd think of them as a friend. However, recently I've started to develop feelings for a close friend I've known for over four years...We met four years ago in uni. We did the same degree and have similar backgrounds so we and a few other friends quickly formed a pretty close social circle. We are both Asian and come from pretty conservative cultures so neither of us are out to our friends (I didn't know he was gay when I first met him). He's a really nice guy with a relatively reserved personality and really good manners. He works out a lot so he is in pretty good shape and all the girls find him attractive. However, in the past four years he's never dated anyone (at least not to our knowledge) so our mutual friends all just assume he has super high standards. When people say they want to introduce girls to him, girls who find him attractive would just say "I'm sure he doesn't need help".I had this assumption for a while too, thinking he was probably just really focused on his studies, until two years ago, to my surprise, when I was checking out the app store on my phone, I found a section by accident where I could see all the apps rated/recommended by my friends. I saw a gay dating app rated 4 stars by him. I was quite surprised but didn't think too much about it, because to be honest he's not really my type. At this point we were already pretty good friends, so I didn't want to tell anyone about it. I understood how conservative people from his culture could be.A year ago, we had both graduated and moved to a big city for work. Both of us were new to this big city so we started hanging out one on one more with each other, as we didn't have many friends here. We became even closer than before but I never wanted to let him know that I knew he was gay, nor did I find it necessary for me to come out to him. Interestingly, I randomly checked the app store again and saw another gay dating app rated by him. I was quite amused by his habit of rating his apps... Though I'd known that he was gay for a little while, that served as another confirmation that dispelled any doubt about it.A few months later, I decided to give tinder a try. I guess anyone who's reading this can guess where this is headed...I saw his profile!!! I guess he was really eager to meet someone lol (and failed at this being closeted thing). But this time it's a bit different, because previously I had only seen the apps he rated without seeing his actual profiles/pics on those apps, whereas on tinder he actually had quite a few clear face pics. To my surprise, one of them was one of me and him. I didn't know how I was supposed to feel about that.Last week we had a farewell dinner with him because he was leaving for a new job in another city. Our mutual friend and I decided to print some group photos and get them framed as a gift for him. When he looked at the photos I had printed for him, he looked at the one of just me and him (the one he had on his tinder profile), and said he really liked that photo. I felt quite moved somehow.After dinner, we and two other friends walked together to the train station. Conveniently, these two other friends went straight to their respective platforms right after saying goodbye to him, leaving just the two of us at the concourse. I thought I'd just say goodbye to him and give him a brief hug. But to my surprise, he stood in the middle of the concourse, looked me in the eye, and talked to me rather slowly in a very soft tone. He said he could show me around if I went to the city he was moving to. I felt quite touched so I gave him a pretty solid hug, said all the best to him, and then walked towards my platform. Before I walked down the stairs, I looked back and saw him looking at me, waving me goodbye.After I got on the train, I started wondering what had just happened. I never thought about "us" for the past four years, but I was touched and felt a bit sad that he was leaving. Then I realised, I've been trying to find the right one for so long without realising that we are probably the most compatible people out of all my friends and of all the guys I've hung out, slept or gone on a date with over the past four years.I thought about this for a while, so I decided to text him the night before his flight. In the text message, I wished him all the best and said "I wanted to say some things I'm not sure if I should say at all...I know we are both very private people and rarely talk about our private lives to each other or other people. I just wanted to let you know that I think you're a very special person and I'm sure I'll miss you. And I really like that photo (of us) too." He replied the next morning stating he felt lucky to have me as one of his best friends and that he would "try to come back to [our city] soooooooon[sic]!!!".I feel extremely conflicted now. This friendship is definitely one of the best. For me, that also means that if we date, we probably won't fight too much as I'm sure our personalities match. I definitely have feelings for him now but he's so closeted there's no way I can know if he feels the same. He could be not interested in me at all or just too closeted or feel too afraid to ruin this friendship like me...I don't think anyone can offer any solution to this problem since he's so hard to read. I just thought I'd share this story here and see whether there were people in the same boat... Love is a difficult thing, isn't it?