If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. 1 John 1:9.
It is only when we have experienced genuine repentance that we can make a genuine confession. Perhaps one of the best ways to test the genuineness of a confession is to realize whether or not there is any excuse added to the confession. If I come to you and say, "I'd like to ask you to forgive me. I am sorry that I lied about you, but if you weren't such an ugly person I wouldn't have lied in the first place," you can know immediately that I have not had genuine repentance!
The problem of self-justification began in Eden. Adam blamed Eve for his problems, and Eve blamed the serpent. We are told that "when sin has deadened the moral perceptions, the wrongdoer does not discern the defects of his character...and unless he yields to the convicting power of the Holy Spirit he remains in partial blindness to his sin....To every acknowledgment of his guilt he adds an apology in excuse."--Steps to Christ, p. 40.
There is no chance whatever for genuine reformation apart from repentance. Have you ever had someone tell you to "say you're sorry"? Did that make you sorry? Have you ever told someone else, perhaps your children, "Tell them you're sorry"? Does that make them sorry? Unless we are truly sorry, our confessions will be worthless, and no reformation will result. We all know by experience that we cannot reform ourselves, but as we get a glimpse of Jesus, and see the disappointment on His face, and see His love for us and His long-suffering, then we will experience true sorrow for sin.
It is only as we accept the mercy and the compassion of Jesus that He can, through us, pass on His mercy and compassion to others. Jesus is the only One who can give you peace. He loves you. He gave Himself for you. He will not judge you unfairly. His heart of love is touched with the feelings of your infirmities. As we come to understand His love and how much pain we have brought to His heart by our sins, we will be truly repentant, truly sorry for what we have done to hurt Him. The confession that springs from sorrow for hurting One who loves us will not give excuses, but will be heartfelt. And the result of that will be reeformation.