In ch.15, Anne listens to her father and sister gushing about Mr. Elliot:

[Anne] could only offer one solution [why Mr. Elliot should want to be received back into the Elliot fold]: it was, perhaps, for Elizabeth's sake. There might really have been a liking formerly, though convenience and accident had drawn him a different way; and now that he could afford to please himself, he might mean to pay his addresses to her. Elizabeth was certainly very handsome, with well-bred, elegant manners, and her character might never have been penetrated by Mr. Elliot, knowing her but in public, and when very young himself. How her temper and understanding might bear the investigation of his present keener time of life was another concern, and rather a fearful one. Most earnestly did she wish that he might not be too nice, or too observant, if Elizabeth were his object.