Relate the resolution of this story from Mme. Forestier's perspective.

Mme. Forestier barely recognizes Mathilde and cannot believe what she's hearing. She likely questions in her mind why Mathilde would not have been honest with her..... why she would lie. And she likely sees her friend as rather foolish. Most of all, I would presume she feels sorry for Mathilde, but sees her as a fool none-the-less.