Repentance is not merely reporting your sins to God. God is already quite aware of them. Repentance, instead, is the decision to also become aware of your sins and turn away from them, even when (especially when) those sins are enjoyable.
Repentance must be proceeded by conviction. Conviction is not something we can scrape up within ourselves. Conviction is only ever a gift from God.
How is conviction a gift? Imagine you used to enjoy frozen, cardboard pizza. Not only enjoyed it, but thought it was the best pizza because you had never had any other kind. And then someone hands you the best slice of Chicago deep dish. Or New York thin crust. Or Neapolitan with fresh mozzarella. Your eyes are open to what pizza can really be like. And, you realize, you'll never be able to enjoy cardboard pizza ever again. Or, when you do go back to it, you know you're settling for second best.
That's what conviction is like. It makes what used to be enjoyable unenjoyable. But only because you have experienced the real thing, not the mere shadow.
C.S. Lewis puts it like this, "It would seem that Our Lord finds our desires not too strong, but too weak. We are half-hearted creatures, fooling about with drink and sex and ambition when infinite joy is offered us, like an ignorant child who wants to go on making mud pies in a slum because he cannot imagine what is meant by the offer of a holiday at the sea. We are far too easily pleased.”