Compassion and Forgiveness Quotes in I Know This Much is True

How we cite our quotes: (Chapter.Paragraph)

Quote #10

She watched it swing, pendulum-like, before her—watched the reversal of the dark magic she had witnessed long, long ago. "Forgive me," I whispered. (47.290)

We're not sure why Dominick is asking Prosperine for forgiveness. Is it so he can rest better, knowing she has forgiven his grandfather, or is it so she can let it go?