Read it through once

“No, no you may be sure of that,” said Estella. “You may be certain that I laugh because they fail. O, those people with Miss Havisham, and the tortures they undergo!” She laughed again, and even now when she had told me why, her laughter was very singular to me, for I could not doubt its being genuine, and yet it seemed too much for the occasion. I thought there must really be something more here than I knew; she saw the thought in my mind, and answered it.