How do i know if this guy has a crush on me??? :/?

well there is this guy and we flirt with each other subtly. and today we were watching a movie in cl (i sit by him) and him and his friend were talking about who they like and he wouldnt say who it was. and he stands up for me when someone makes a harmless joke. i really like this guy so do you guys think he likes me plz answer i have been crushin on this guy for awhile.