Lady Russell, whom [Anne] had always loved and relied on, could not . . . be continually advising her in vain. She was persuaded to believe the engagement a wrong thing; indiscreet, improper, hardly capable of success, and not deserving it.

The premise of Persuasion hinges on Lady Russell persuading Anne not to marry Wentworth. Had Lady Russell not talked Anne out of the engagement, there would be no story for the novel to follow. Upon reflection in Chapter 4, Anne justifies her reasoning to herself and the reader by emphasizing Lady Russell’s role as a mentor and maternal figure in her life. Anne trusts and values Lady Russell’s opinion, so the fact that Lady Russell clearly and repeatedly tried to convince her to give up Wentworth held weight for Anne. Anne is not certain whether Lady Russell’s advice was correct, but she knows Lady Russell genuinely believed what she was saying, and Anne thinks she did the right thing to listen to her mentor.

It is the worst evil of too yielding and indecisive a character, that no influence over it can be depended upon. You are never sure of a good impression being durable; everybody may sway it. Let those who would be happy be firm.

In Chapter 10, Wentworth tells Louisa it is easier to be happy if someone is not easily persuaded. He claims it is easier to trust someone else when their opinions are steady. He holds this opinion because Anne changed her mind about marrying him. However, Louisa takes his advice to the other extreme. In trying to make Wentworth love her, Louisa becomes increasingly stubborn, which eventually leads her to injure herself in a fall. After Louisa’s accident, Wentworth blames himself and starts to see how being completely unyielding has its drawbacks as well.

She thought it was the misfortune of poetry, to be seldom safely enjoyed by those who enjoyed it completely; and that the strong feelings which alone could estimate it truly, were the very feelings which ought to taste it but sparingly.

In Persuasion, Austen generally treats the tendency toward or against persuasion as an inherent character trait. Anne adopts the same philosophy when she advises Captain Benwick to read something other than poetry while he is grieving. As the narrator reports in this passage from Chapter 11, Anne believes that if a person is likely to be deeply affected by the emotion of poetry, they’d best read it only “sparingly.” However, she also believes the people most prone to melancholy are the ones more likely to fully appreciate poetry. Benwick does prove to be easily swayed by the emotions of the moment when he falls in love with Louisa. Although Anne and other characters are skeptical about the long-term sustainability of Louisa and Benwick’s love, Anne concedes that it would not have been possible in the first place had both parties not been open to change their desires to fit their circumstances.

He had imagined himself indifferent, when he had only been angry; and he had been unjust to her merits, because he had been a sufferer from them. Her character was now fixed on his mind as perfection itself.

Captain Wentworth, who claims throughout the novel to be stalwart, steady, and unchanging, realizes that his surroundings shape his perception, and therefore his behavior. Although he loves Anne the whole time they are separated, he reinterprets that love in ways that foreground his anger, sadness, and disappointment. As much as he thinks himself above persuasion and change, his emotions powerfully influence his perspective on Anne, as demonstrated in this passage from Chapter 23. When he knows she loves him, all the things he saw as flaws become reasons to love her.