Since the previous book was about the "Passion of Love," this book will probe the notion of love even further. The narrator defines love by means of four points: first, there are minds that do not experience love; second, love cannot be ruled by lust; third, love does seek self-satisfaction; lastly, when love acts toward one of the opposite sex, it appeals to lust for help. The narrator believes many people exist who enjoy giving happiness to others and this is the highest form of love.
Back at Western's house, everyone celebrates Allworthy's recovery except for Sophia. Her father does not notice Sophia's melancholy, but Mrs. Western, who has "lived about the Court, and seen the World," quickly discerns that Sophia has fallen in love. Although Mrs. Western has not suffered this state herself, she is as well read in love as she is in politics. When Mrs. Western tells her brother that Sophia is in love with Mr. Blifil, Western is furious that Sophia has fallen in love without his permission. Mrs. Western pities his "Country Ignorance," while he scorns her "Town Learning." Mrs. Western eventually wins the Squire's approval of the match, but he worries that Allworthy will not agree to it, since "Money hath no Effect" on him. The Squire believes that "Petticoats should not meddle" in politics, but when Mrs. Western threatens to leave, the Squire remembers that he is to inherit her fortune, and tries to mollify her. She suggests that they "sign a Treaty of Peace."
Sophia suspects that her aunt has realized her affection for Tom, and she attempts to conceal her feelings by paying more attention to Blifil than to Tom. This baffles Mrs. Western, who reckons that Sophia's behavior must be "extreme Art in Sophia" to deflect her from the truth. Mr. Western invites Allworthy to dinner and proposes a match between Sophia and Blifil directly afterward. Allworthy considers the "Alliance" to be a sensible one, and greatly praises Sophia. He appreciates Sophia's grand fortune, but will only ratify the plan only if Sophia and Blifil profess mutual tenderness. This answer upsets Western, who believes that parents have a better knack for choosing marriage partners than their children. The narrator suggests that Allworthy is an avatar of moderation.
Allworthy proposes the match to Blifil, who admits he has not once entertained the thought of marrying Sophia. His appetites, the narrator confides, are so moderate that they can easily be supplanted with philosophy or study. Since Blifil does possess a healthy portion of "Avarice and Ambition," however, he gravitates toward the idea of Sophia's fortune. Allworthy disapproves of the cold answer from Blifil; Allworthy himself "possessed much Fire in his Youth, and had married a beautiful Woman for Love." Blifil subdues Allworthy's concern with a learned exposition on "Love and Marriage." Allworthy and Western, by letter, arrange a courtship opportunity for the young lovers.
Mrs. Western finds Sophia reading in her bedroom and they debate the merits of the book. Mrs. Western tells Sophia that she has long perceived the aura of love about her. Sophia need disclose her passion no further, since Squire Western has proposed the match to Allworthy, who has wholeheartedly complied. Sophia, overcome with surprise and joy, blurts out: "So brave, and yet so gentle; so witty, yet so inoffensive; so humane, so civil, so genteel, so handsome! What signifies his being base born, when compared with such Qualifications as these?" The words "base born" alert her aunt to the fact that they are talking about different men. Mrs. Western is enraged that Sophia can consider dishonoring the prestigious Western family line by marrying a bastard. Sophia begs Mrs. Western not to tell her father her secret. Her aunt agrees on the condition that Sophia will agree to meet Blifil that afternoon.
Mrs. Honour finds Sophia in tears and begs Sophia to tell her what has happened, even though she has, in fact, been listening to the conversation through the keyhole. Mrs. Honour responds to Sophia's dire news with a long speech in her country dialect. She believes Sophia should be free to choose the man she finds "most handsomest." After Honour mentions having seen Tom walking by the canal that morning, Sophia immediately dons her hat, but, deciding that the ribbon in the hat does not suit her, orders Honour to fetch her another. The ribbon exchange results in Sophia's missing Tom by a few minutes. The narrator takes this opportunity to warn all female readers against vanity.