If you want to search your heart to see what's in there, do not do it by yourself, for you are not capable of understanding yourself thoroughly. Instead, go before the Lord, open your heart up, and ask him to search it. And he will help you see what he sees and what shouldn't be there. Then ask him to cleanse and heal you heart. This conforms to the smart practice of always entrusting God to do the hard work for you. This is how you get to live a life carefree in the Lord. We struggle so hard on our own to do so many things, forgetting that God can accomplish what we want to achieve for us. Good example, to attain union with God, a lot of people dismiss it for being too hard. But ask the Lord to do the work to prepare you and it becomes totally attainable. Just remember that we are weak and God is super strong and eager to help.