Question: how to know if a guy has a crush on you online?
Answer: He replies instantly. If the guy truly likes you then he would not wait for six hours and then give you a reply. ... 
He compliments you. ... 
He shows interest in getting to know you. ... 
He tries to make you laugh. ... 
He respects your personal time. ... 
He knows his limitations. ... 
He is consistent and persistent. ... 
He asks about your day.