To say "I'm sorry" is to express what is already known to God.
Saying "I'm sorry" to God frees me from that thing I've done for which I cannot forgive myself; that thing for which God has no interest in punishing me, but for which I have already begun to punish myself: through guilt, or shame, a diminished sense of well-being, or a desire to hide. Saying "I'm sorry" brings into my consciousness the very thing I’ve tried to bury. Expressing it holds me accountable.
I tell God "I'm sorry," and I'm forgiven, though sometimes I'm slow in accepting the forgiveness. I have to remind myself I really am loved “in spite of." Forgiveness enables me to let go and move on, unencumbered.