Im in 사랑 with my neighbour who is in 사랑 with his gf... But i think he may have feelings for me! I 사랑 him and it hurts seeing him with someone else please help me!

Hi!
I am not good about love... Anyway I'll try to help 당신 (if I can)...
First at all, if 당신 think he has feelings for you, so 당신 speak with him ? (don't know how to formulate it, sorry).
If 당신 do, 당신 must be sure he really has feelings for you. (maybe not "love" in the meaning of love, but... something.)If 당신 laugh together (or something like that) 당신 could tell him something like "yes I know 당신 사랑 me" (laughing of course). Just to see his reaction. A friend of mine did that and it helped her. Yep, I'm sure it's not easy to say that to someone 당신 love, but if 당신 think 당신 can... just say something like that, without being serious. (complicated to explain I'm sorry).

If 당신 don't think he loves 당신 (it sounds brutal, I'm really really really sorry), the best think 당신 can have is "if he's happy like that, I must be happy for him". I know that it's difficult but it's better than jealousy. He would be embarrassed ...

I'm sorry for two reasons : first, because I'm not good at English (I'm French), and second, because I am not good about love. (I help my 프렌즈 but it worked with only two...)
Hope 당신 understand me ...