"That we were commanded to confess before The Eternal to all the sins we committed, at the time we are remorseful over them. This is the substance of the confession that a man should say at the time of repentance: "I pray Thee, O Eternal One: I sinned rebelliously and committed iniquity deliberately, thus and so"; in other words, he should mention the sin he did explicitly, in words (lit. with his mouth, so R. Judah b. Bava in TB Yoma 86b), and beseech forgiveness for it; and let him continue at length about the matter, according to the eloquence of his tongue."(Sefer Hachinuch "For the Month of Tishre" p. 37, italics mine)
It is not enough to confess, to admit, to speak words asking forgiveness. We have to be remorseful, which means understanding. Remorse is more than just feeling badly; it's appreciating where the sin came from, what part of our woundedness burst forth. Remorse means we fully understand the extent of our actions, where they came from, and what damage they wrought. Only then can we fully put to words, with our mouths, explicitly, our own request for forgiveness.
Is that hard? Yep. It is the hardest, for it isn't just about looking at the action, but deep inside, without making excuses or dodges--either for yourself or the Other.
What do you finally understand, and are remorseful for? What do you finally understand and forgive in others?