As is always the case in her novels, Austen uses narrative point of view to direct how we understand the story that unfolds. In this case, she tells the story largely through the eyes of Anne Eliot. We know what Anne knows, and we are ignorant of what Anne does not know. This creates suspense and surprise: for example, we are as oblivious as Anne to the love affair between Mrs. Clay and Mr. William Eliot until they run off together. Likewise, we don't learn of Mr. Eliot's true, cold-hearted character until Anne hears this news from Mrs. Smith.
Rhetorical devices are persuasive devices, and narrative point-of-view acts as a rhetorical device in this novel, persuading us that Anne, the narrator, is a sympathetic and admirable character. However, Austen uses other rhetorical devices as well. For example, the autumnal surrounding of the opening of the novel helps persuade—or misdirect us—in the beginning that Anne's best days are behind her and that she has little to look forward to but a fading, melancholic future. The slow, autumnal rhythms of Anne's life, sorrowful because she threw away the chance to marry the man she loved, are reinforced by long sentences as well as allusions to Romantic poetry. Austen then uses dialogue to argue persuasively that women are not inconstant, an accusation Wentworth directs against Anne.
As many critics have noted, Austen's style in this novel, though still comic, moves away from the broad comedy and sometimes epigrammatic prose of earlier works, such as Pride and Prejudice, to a more serious tone that anticipates the Victorian novel.