The way h+l look at each other, even if it's just a short glance. They're so intense/passionate about it. It feels like we're interrupting. When they look at each other with all that fond it feels like we walked in on them in their bedroom or something. Like I'm compelled to say "oops so sorry for interrupting, please continue I'll just be going now" even though they're on stage in front of thousands of people. No one else exists when they're looking at each other like that.
and that’s exactly how I know they are in love