Jeremiah talks about being good stewards of our hearts. The hypothesis is that all of us, in one way or another, have lost heart in our relationship with God. The experiment is to ask Jesus Christ for healing, and to entrust our beings to Him completely.
If we are willing to be tender, honest, and vulnerable—that is, brokenhearted—God is able to heal us. This is the promise of Psalm 147:3! Then, when we are healed by God, it allows us to live life without being controlled by our hurts.