She says
My reason was this: I had learned what it is to love–and I knew that I had never loved you–never. I wanted to hurt you so much that you would leave me. I wanted to hurt you in such a way as to keep you from ever coming near me again. I was afraid that if you did forgive me and take me in your arms, you would feel me shudder, and see the terror and loathing in my eyes. I wanted–for even then I cared for you a little–to spare you that. Did you notice the date? It is the eighth of June. Do you remember what day that is? We used to celebrate it once a year. It is the day–
(the leaf flutters to the table in front of him)
–the day of our first kiss.