He was not Mr. Wentworth, the former curate of Monkford, however suspicious appearances may be, but a Captain Frederick Wentworth, his brother, who being made commander in consequence of the action off St Domingo, and not immediately employed, had come into Somersetshire, in the summer of 1806; and having no parent living, found a home for half a year at Monkford. He was, at that time, a remarkably fine young man, with a great deal of intelligence, spirit, and brilliancy; and Anne an extremely pretty girl, with gentleness, modesty, taste, and feeling. Half the sum of attraction, on either side, might have been enough, for he had nothing to do, and she had hardly anybody to love; but the encounter of such lavish recommendations could not fail. They were gradually acquainted, and when acquainted, rapidly and deeply in love. It would be difficult to say which had seen highest perfection in the other, or which had been the happiest: she, in receiving his declarations and proposals, or he in having them accepted.
A short period of exquisite felicity followed, and but a short one. Troubles soon arose. Sir Walter, on being applied to, without actually withholding his consent, or saying it should never be, gave it all the negative of great astonishment, great coldness, great silence, and a professed resolution of doing nothing for his daughter. He thought it a very degrading alliance; and Lady Russell, though with more tempered and pardonable pride, received it as a most unfortunate one.
Austen manages to make most of her female readers good and in love with Captain Wentworth themselves in this chapter, and I posit that she manages it using the following devices:
1. He is described in glowing terms, and, since Anne is the one person introduced in the novel so far who readers can attach to without feeling like they're rooting for a numbskull (Elizabeth) or a popinjay (Sir Walter) or someone on the make (Mrs. Clay and, to some extent, her father, Mr. Shepherd) or someone who places improper emphasis on rank (everyone I've just mentioned except Anne, plus Lady Russell).
2. Anne has already earned reader sympathy by being somewhat of an underdog - her father and her sister Elizabeth have been set up as fools, and they don't value Anne. Lady Russell, who is intelligent but a bit too fond of titles and money, adores Anne and has helped us to see her as a person of good character and real value. So if Anne loved - and still loves - Wentworth, then we sympathetically attach to him as well.
3. Wentworth himself is established as an underdog. Despite all his heroic traits (physically and intellectually), he is sneered at by Sir Walter (which can only raise him in readers' eyes) for his lack of fortune and rank. He is disliked by Lady Russell for traits that are presented as good traits - ambition in his career and a positive outlook that he'll soon make his fortune.
4. We learn that Anne deeply regrets having broken the engagement, that she still harbors feelings for Captain Wentworth, and that she wishes she had not done so.
How can we not all be inclined to love Captain Wentworth, under those circumstances? And, I might add, it's a good thing, too, or else we might not care for him all that much or bother to try to explain or understand his behavior when he and Anne eventually meet. And no, I don't consider that a spoiler, because if you've read any Austen or know anything about her work at all, you're already expecting it to occur.
Lady Russell's role
Lady Russell has essentially appointed herself Anne's fairy godmother, without the magic wand or gifts of nice clothing. And while I found myself exceedingly pissed at her for interference the first couple of times I read Persuasion, I believe it worth the time to examine her reasoning.
1. Anne was the daughter of a landed, titled gentleman; Wentworth is an aspiring naval officer with neither land nor money. Sir Walter had already said he'd do nothing for Anne, meaning no dowry and no support after her marriage.
2. Anne was only 19, and, at the time, quite pretty. She could make a more stable match, rather than attaching herself to a man who would be at sea all the time and, given his daring nature, willing to take a lot of risks in order to advance his career and his winnings. (Men in the navy split up the "winnings" when an enemy ship was captured, just as pirates did, frankly. So a daring officer willing to take lots of risks in engaging the enemy could gain a large amount of wealth, but in doing so, he was risking death on a regular basis.) Anne would be alone quite often, without any support from her father, and might face difficult times financially, to say nothing of the great risk of her being made a young widow.
3. Lady Russell didn't fully grasp the depth of Anne's affection, and thought it was merely an infatuation. She believed that with Wentworth gone, Anne would readily find someone else. Instead, she faded away. But Lady Russell didn't know - and couldn't have known - that when she advised Anne to break the engagement.
Why Anne broke it off
You will note that Anne was willing to proceed with her marriage despite her father's disapproval, since he did not outright forbid or oppose the marriage. Lady Russell, however, who was for all intents and purposes standing in the role of mother to Anne at that age, did outright oppose the marriage, offering quite a number of reasons as to why the match should not proceed. In deference to Lady Russell's pseudo-parental role, Anne allowed herself to be persuaded to call off the match due to Wentworth's lack of funds. This brings us to one of my favorite sentences in the book:
"She had been forced into prudence in her youth, she learned romance as she grew older: the natural sequel of an unnatural beginning."