This week's readings shed a bit more light on this topic. Willoughby and Marianne are contrasted with Edward and Lucy. Edward is engaged, but Willoughby was very careful not to do anything that would make Marianne think they were 'postively engaged.' But he did enough to make Elinor, Mrs. Jennings, and probably all their other acquaintance think that they were. Indeed, Mrs. Jennings says his taking Marianne to Allenham and showing her all over the house and grounds made her think they were. So, Willoughby avoids any chance of Marianne suing him for an actual breach of promise, but still, as Lizzie said about Jane Bennet, exposed her to the world's "derision for disappointed hopes."