The cost of being persuaded against your own judgment
Anne gave up Wentworth because she trusted others over herself. The novel tracks what that decision cost her and whether she can reclaim what she lost. Austen frames Anne's original compliance as understandable but wrong, and the whole plot is the proof.
Class and social rank as a corrupting force
Sir Walter Elliot measures every person by their title and appearance. His vanity drives the family into debt and blinds him to his daughter's worth. Wentworth was rejected partly because he lacked rank. The novel shows the damage this system does to real people.
The reliability of first impressions and surface charm
William Elliot is polished, attentive, and well-spoken. He is also a schemer. Wentworth seems cold and indifferent. He is still in love with Anne. Austen repeatedly shows that the surface reading is wrong, and that careful observation over time is the only way to see clearly.
Women's constancy versus men's freedom to move on
Anne's argument to Captain Harville, that women feel as deeply and as long as men do, is the novel's thesis statement. Men like Wentworth can channel grief into action and achievement. Women like Anne have to sit still and endure. The novel validates Anne's inner life as real and serious.
Second chances and the possibility of repair
The novel asks whether a relationship broken by outside pressure can be rebuilt. Austen's answer is yes, but only if both people are honest about what happened. Wentworth has to admit his pride kept him away. Anne has to explain that she acted on bad advice, not a change of heart.