When I am meditating sometimes I have trouble distinguishing whether I really feel my heart or whether it is my mind that I am experiencing.
If it is really your heart, then you will get a sense of pure satisfaction. If it is the mind, you may get satisfaction, but immediately you will also get doubt. Your experience will be attacked by other thoughts: "I am so bad, so impure, so ignorant. This morning I told a lie and yesterday I did something else that was bad, so how can I have this kind of satisfaction?" When that kind of idea comes, you will know that your experience was from the mind.
When you get an experience from the mind, you may temporarily feel very happy. But the joy will not remain, because you will not be able to establish your identification with what the mind has seen or felt or realised. But once you get an experience from the heart, immediately you will feel your oneness with it, and your joy will be lasting.
When you see a flower with your mind, you appreciate and admire it. But when you see it with your heart, immediately you feel that your heart is inside the flower or that the flower is inside your heart. So when you have an experience, if you are one with the experience itself, then you will know it is from the heart. But if you feel that the experience is something that you are achieving outside yourself, then it is from the mind.