There is a big difference between love and unconditional love. Unconditional love has no strings attached. It does not require some action in return. It is simply the act of dying to self. Unconditional love says, no matter what you have done, I forgive you because I love you without reservation.
The Bible says that, "love is patient, kind, long-suffering. It does not envy; love does not parade itself, it is not puffed up; love does not behave rudely, does not seek its own way, is not provoked, thinks no evil; does not rejoice in iniquity but rejoices in truth;it bears all things, believes all things, hopes all things, endures all things. Love never fails." (1 Corinthians 13:4-8) Wow, now that's love and although I have come a long way in learning to love unconditionally, I must confess, I am still working on this.
King David is described as, "a man after God's own heart" (1 Samuel 16:7&13) yet, he certainly wasn't a sinless person. On the contrary, he committed adultery, murder, deception - a series of failures that would match or surpass any of ours. In fact, if he were on trial before the Christian community of his day, I dare say they would have written him off long ago. However, David did recognize when he had sinned against God and sought His forgiveness in true repentance. To know David's heart, all we need to do is read his Psalms. When David penned the Psalms, he did not know they would be preserved and studied for centuries. He was simply writing love letters, expressing his unconditional love for God - bearing his soul, praising His God no matter what he was going through.
Like David, we all have our own faults, sins, failures and struggles. God knows them because He knows us, our weaknesses. He knows we are imperfect, but He loves us unconditionally anyway. So much so that he has made a way of escape for our failures just as he did for David.
The Truth
"If we confess our sin, He is faithful and just to forgive us our sin and to cleans us from all unrighteousness." (1 John 1:9)