To be completely honest, love isn't just one emotion. If love was happiness then why don't we just say "You make me happy..." instead of "I love you" or "I'm in bliss" when we mean to say "I'm in love"? Love...means you care for someone. You put their needs above yours, and sometimes it sucks because sometimes the one you love doesn't care about you and THAT is when love is pain. Mind or Heart? Neither.
Trusting your "heart" would be trusting your emotions, which are extremely misleading, let me tell you. Then again, your "mind" may over think things and lead you straight into a trap. Love isn't easy, same as life. It all depends on the situation, but I'll give you a tip. If something is truely worth you putting "love" into it, you'll feel it. Like someone posted before about going with your gut, in the back of your tricky mind you always know the answer. People give off vibes and you do pick up on them, whether you realize it or not, you'll find sometimes in the back of your head you secretly know the outcome of a situation with somone.