The only way that Lily sees to preserve that goodness in Ryle—not just for him or her, but for their daughter—is not to allow any more opportunities for what is evil in him to overshadow what is good. It is that love and goodness that Lily calls upon when explaining her decision to Ryle. The directness of Lily’s question is painful for Ryle, but that pain helps him realize his own truth in the way Lily’s pain allowed her to understand hers.