Is the heart really resposible for love?

Actually, not really.

Scientifically, your brain is where emotions and feelings are created, therefore, your heart doesn't really have anything to do with it. Obviously when you're feeling emotional around someone you love, your heart rate can increase, causing you to feel it in your chest. But, thats caused by the brain too. The brain controls everything in your body, so technically the brain is the main organ involved with love. The heart just kinda does what the brain says.