When the king's visit is over, Julien hangs around the room that the Marquis de La Mole stayed in. He finds a piece of folded paper that contains a note written by a guy to the Marquis who wants a government post that's about to open up.
In the coming week, one of the biggest points of gossip in town is how Julien was allowed to ride with the Honor Guard. Even people who usually preach equality are furious with a carpenter's son being honored in this way. People suspect that Madame de Rênal put in a good word for him because he's handsome.
Soon afterward, Madame de Rênal's son falls ill with a fever. She thinks that God is punishing her for having an affair with Julien. She tells Julien that she's going to spill her guts to her husband. Julien tells her not to.
One day, Madame falls to her knees and tries to tell her husband that their son's illness is all her fault. But he thinks she's just being crazy and won't listen to her.
Julien thinks about going away for a while. But he knows that Madame will tell her husband everything if he leaves.
Julien has a long talk with Madame that ends with them both crying and swearing to stop their affair.
Eventually, Madame's son regains his health. Madame's remorse stays strong though, now that she's accepted the sinfulness of what she's done.
The servant Elisa (who used to be in love with Julien) becomes so frustrated that she one day goes into town and tells Monsieur de Rênal's rival, Valenod, that Madame is sleeping with Julien Sorel. It's not clear whether she knows this for sure or is just talking out of suspicion.
The news hurts Valenod's pride, since he has been trying to sleep with Madame de Rênal for years.
Next thing you know, Julien sees Monsieur de Rênal reading an anonymous letter explaining everything going on between his wife and Julien. The man's face darkens as he reads.