This is an age long debate...that of the heart vs the mind. Which is stronger and which is wiser...I don't think anyone has ever been able to successfully conclude that one. Just thought I will share some thoughts on this one...including some guidance I got from a Brahmakumari. My belief is that the thoughts lie in the mind but when we symbolically divide the mind and the heart, we are really talking about thinking and feeling.
Thinking is a function of the mind and mind is a part of our body...so it becomes a direct function of the body. Thinking is the process of picking thoughts, of one's own or other's and processing them to make sense of them or ultimately lead to some action. Feeling is only about the vibrations or a thought directly generated from our intellect or our higher self. When we sit down peacefully and try to concentrate on any issue / life situation, there are feelings we get about them which could be thoughts from our own higher self or our guides. If one can identify when it is a pure feeling vs when it's a desire created by your own mind to tempt you to something radical, that is when one can really start the journey of wisdom.
I attended a Brahmakumari Raj Yoga session a few days back and this topic crept up and while she was explaining it, I asked her how is it that one can identify when is it that it is an inner voice or your own desire tricking you. It was a very profound answer she gave me. She said when the inner voice speaks, the message is universally accepted without resistance and if one faces resistance within, its an indicator that its a trick of your own mind :)