What is the central theme of Persuasion?

The central theme of this novel is that a young person in love must weigh the feelings in her heart against the prudent advice of a trusted elder. The message is that love matters, and one must trust oneself.
The young Anne Eliot makes a mistake in not fully trusting in her feelings for Frederick Wentworth. She wants to marry him. They are both in love. But her aunt, Lady Russell, persuades Anne to break off the marriage engagement. Wentworth's economic prospects are uncertain, and Lady Russell fears Anne will end up poor and full of regrets if she marries him, especially if he is unsuccessful in his naval career.
Anne follows her aunt's advice but lives to regret it deeply. She did not pay enough attention to her own feelings. Because she loves Wentworth, she turns down a marriage proposal from the well-off Charles Musgrove, who ends up marrying her older sister. She becomes, by 26, a marginalized spinster who nobody treats as important. When Wentworth returns to the neighborhood a wealthy and successful captain, Anne has every reason to believe she should not have allowed her aunt to persuade her break the engagement.
This is perhaps the most Romantic and autumnal (full of regrets for times past) of Austen's novels. In all her novels, she shows the plight of women on the marriage market with little money, who are torn between economic prudence and love. In this novel, true love wins out and is united with money, but not until after many years have been wasted when Anne and Wentworth could have been together.

Self-evidently, persuasion is a major theme of Austen's last book. Seemingly everyone in the story suffers from some malady related to persuasion.

Mr Shepherd, Sir Walter's financial agent: persuades Sir Walter to rent out ("let") the ancestral manor, Kellynch Hall.


Mrs Clay, daughter of Mr Shepherd: has persuaded Elizabeth and hopes to persuade Sir Walter of her indispensability (she does so persuade cousin William Elliot).


Captain Benwick, friend of Wentworth: Anne seeks to persuade him out of his depression while Louisa does persuade him through new love.


Mrs Charles Smith, Anne's friend: suffers terrible loss because of what she and her husband were persuaded to do.


Henrietta Musgrove, sister of Louisa: persuaded to marry her less-than-wealthy cousin, Charles Hayter.


William Elliot, heir and cousin: among many other things, seeks to persuade Anne to persuade Sir Walter to reject Mrs Clay's advances.


Anne Elliot: persuaded to abandon her beloved by rejecting a long engagement because of his lack of money.


Lady Russell, family friend and Anne's mentor: persuades Anne against the imprudence of a long engagement with no certain outcome to Wentworth's Navy prospects.


Elizabeth Elliot, Anne's elder sister: previously persuading herself that she is superior to all her former suitors and so is now alone.


Sir Walter Elliot, a baron and father of three daughters: persuading himself that social demands outweigh practical realities and that a baronetcy (the lowest hereditary noble order given) provides unassailable social clout and prestige.