Arriving in a great state of agitation, Willoughby persuaded Elinor to listen to his story. He told her that, at first, he had not been serious about his involvement with Marianne and looked at it as only a boost to his ego. But he fell in love with her and decided to become engaged to her. However, the day before his intended proposal, Mrs. Smith, his relative, discovered how badly he had treated Colonel Brandon's ward and offered to forgive him if he would marry the girl. He refused and decided to marry the wealthy Sophia. He declared that he had been tortured for his wrongdoing. The letter which he had written to Marianne had been composed by his fiancée, now his wife, who had forced him to copy it after she had snatched Marianne's letter from him and read it. Sir John Middleton had met him the night before and told him of Marianne's morbid condition. Since he still loved her, he had rushed to Cleveland to exonerate himself with her before she died. He was joyous to learn this wasn't necessary, but being already there, he wanted to clear himself with Elinor.
Elinor again shows us her generous nature by allowing the wretched Willoughby to tell her his story and afterwards by feeling genuine compassion for the man who has hurt her sister so terribly.
Willoughby has been the cause of his own troubles and is forced to live with the results of his mistakes. His wife Sophia is painted by him to be selfish and evil tempered. She married Willoughby knowing he didn't care for her. Willoughby is well aware that he sacrificed any hope of domestic happiness for great wealth. Elinor understands him and pities him.