How can you tell difference between heart and mind?
How can you tell the difference between your heart and your mind? How can you really know that it is your heart that is telling you/believing? What if it is only your mind that believes? How can you tell the difference (with anything) that it is really your heart? and not just your mind?
In the Bible the word 'heart' describes the entire person. It is who you are! That includes your mind, your will and your affections. All three are to be involved if we are believing with our heart. You have heard undoubtedly about historical faith (mind mainly) temporary faith (affections mainly) and miraculous faith (will mainly). True saving faith includes all three aspects.
For us it isn't always easy to separate or distinguish them. They mostly merge together. If you love someone, you love him with your mind, your will and your affections. Likewise if we love the Lord. It is a love that is based on what I know of Him (mind). Through the power of the Holy Spirit that knowledge influences my will and my feelings. It makes me willing, it humbles, it draws, it stirs, it wants me to do things for Him. In other words, it is living power of His Word and Spirit that we experience within our heart. For many Christians all the knowledge of God and His Word doesn't change their inner person. They easily live on without a real and close relationship with God. In that sense it only 'mind' (historical faith). But where God's Spirit is working, what I know and learn about God affects my inner being so that my life will change in direction and quality.
May I liken it to human relationships. I use my own example. For several years I lived in the same congregation as my first wife. I knew her, did things in youth-group together, saw her at church. But she never meant anything more to me than any other girl in church. Until there came a day that I 'noticed' her and within my heart a spark began to burn. I wanted badly to know her more and be close to her. Getting to know changed me completely and influenced me for the better. Now I not only did have a 'mind knowledge' but my will and affections were greatly affected. I certainly knew then that I wasn't just loving her with my mind.
In similar ways the Holy Spirit changes us our entire attitude, commitment, feelings, understanding when He draws us to God. It will not only be 'mind' but it will be everything of you. Later the intensity of the feelings etc may ebb away and become more settled, just as in human relationships. But the commitment, will, affections ... so the entire heart is devoted to God.
I hope this will shed some light on your puzzle.