Like from physical or behavioral signs? I know blushing, but what else?
Most Helpful Guy
Blushing does not prove that someone loves you. It happens when people feel embarrassed or self-conscious. Those things are not love.1
Most Helpful Girl
Blushing isn't really love... that's more like a crush.
Love you'll see in their actions. When they go out of your way to do things they know you enjoy. When they start making decisions on plans or what you'll eat, and automatically factor in that you'll be there, keeping in mind how you like things done best. When they're willing to put their pride aside for the sake of moving past any conflict that comes up, because they hate seeing you upset and just want to get back on good terms.
When they'll be willing to stay in, cuddling on the couch with you all night versus going to a friend's party because they know you've been feeling a bit down and when you're happy, it puts them in a good mood as well.1