Not hard.
Say this line
"I like you." then giggle.
Now if you're talking about love you shouldn't be worried about that. Enjoy living life whatever you do, DON'T try to grow up so fast. Not worth the embarrassment and hassle.
Hate to say this but this is a summer camp right? You probably will never see him again even though you'd like to think you will. So I would agree with srkrpt. What do you have to lose? You tell him I like you and he says "Ewwwww gross I hate you." Who cares like I said you'll probably never see him again anyway... Might as well give it a try rather than never knowing and ending up regreting