The day after the dinner, Henry announces to his sister Mary that he will be staying in Mansfield for a while. His entertainment, he tells her to her amusement, will be to make Fanny fall in love with him. Mary tells him that, while Fanny is pretty, she only appears so attractive because Maria and Julia are not around; the challenge, Henry tells her, is in Fanny's lack of interest in him. Henry hardly has a chance to begin wooing Fanny when a letter arrives telling her that her brother William, who is in the navy, will soon be in England. Sir Thomas has invited him to spend the holidays at Mansfield with Fanny. Henry notes Fanny's intense devotion to her brother and decides to use it to his own advantage. William has become a fine young man and impresses all who meet him with his carriage and his tales of adventure on the sea. The obvious delight Fanny takes in her brother and their sincere familial love move Henry, and he decides that he is genuinely in love with her. Sir Thomas notices his attentions to Fanny and resolves to support the match. At a dinner party at the Grants', Henry begins to woo Fanny in earnest, sitting next to her to teach her a card game.
Edmund and Mary's courtship takes yet another turn at the dinner party. Henry begins to suggest improvements to Edmund's parsonage-to-be at Thornton Lacey; Edmund resists, citing practicality and expense and claiming that he likes the place as it is. Mary is obviously disappointed, especially when Edmund states that he plans to occupy the parsonage himself and will not rent it to Henry. Fanny is disappointed too, since she will no longer see Edmund every day. William and Fanny speak of William's imminent departure for his ship. He tells her of his disappointment at not yet being made lieutenant and then talks of how much he will miss her. He says he wishes he could dance with her, and he asks Sir Thomas if Fanny is a good dancer. Sir Thomas does not know, and Henry steps in to try to flatter her. The comment gives Sir Thomas an idea, however; he will have a ball for William and Fanny.
Preparations are quickly made, much to the dismay of Mrs. Norris, who hates to see Fanny benefit. Edmund is planning too: he will be ordained shortly, and then he wishes to ask Mary to marry him, despite his reservations about her. Mary is leaving to visit friends soon; he must act quickly. Fanny is preparing her dress for the ball. William has given her a small amber cross that she wishes to wear, but she has no chain for it. Mary offers to give her one of her own, and, after much reluctance, Fanny chooses one. Once she has chosen, Mary reveals that the chain was a gift from Henry. Fanny tries to return it, uncomfortable with Henry's recent attentions to her, but Mary insists that she keep it. Returning home with the chain, she finds Edmund in her room, leaving her a gift: a much more pleasing chain that he has gotten her for the cross. She tells him about the chain from Mary, and he counsels her to use Mary's chain, so as not to be rude. His praise of Mary nearly breaks Fanny's heart. Edmund then visits the Parsonage to request Mary as a partner for the first two dances at the ball. She accepts the offer but again attacks his career choice, and he decides not to propose to her, a fact which he shares with Fanny. Again Fanny and Edmund discuss Mary's upbringing and her "evil" qualities.
Fanny dresses for the ball. To her delight, the chain from Mary does not fit through the cross, and she must use Edmund's. She decides to wear Mary's chain as well, out of politeness. Lady Bertram, in an act of kindness, sends her own maid to help Fanny dress. The woman arrives too late, but Fanny is touched by the gesture.
The ball is a success. Fanny is given the honor of leading the dancers, and the honor is especially great, for this is the first ball that has been given at Mansfield, despite her cousins' pleas. They are, of course, away from home and will miss it. Fanny at last feels that she is being treated like her cousins. William is to leave the next day, and Henry is to accompany him, taking William to meet with his uncle the Admiral. Mary teases Fanny about Henry. The men are to leave early, and Fanny is tired, so the ball is broken up. Sir Thomas is certain of Henry's affections for Fanny and believes he means to approach him about a marriage.
The incident with the amber cross and the two chains is somewhat similar to the incident with the locked gate at Sotherton that Maria and Henry slither past. The cross and chain, like the gate, convey a great deal of symbolism. Here, though, the focus is on the second of the two love triangles that first came together at Sotherton. The idea of a chain suggests that Fanny will be fettered by choosing a partner. The fact that only one chain fits implies that only one of these men--Edmund--is an appropriate "fit" for Fanny. Behind all this, too, is a certain level of sexual suggestiveness, with the chain being passed through the loop on the cross. The incident brings together the three men in Fanny's life--William, who gave her the cross, and Edmund and Henry, who give her (indirectly, in Henry's case) the two chains. The situation is facilitated by Mary, who has her own interests in mind. The love triangle from Sotherton has become a love quadrangle, with Henry now drawn in to the drama between Mary, Edmund, and Fanny.
The presence of William reinforces the suitability of Edmund as a partner for Fanny. While Henry represents a base, physical kind of love, William represents the ultimate in spiritual, Platonic love. Edmund is a happy medium between the two, brotherly yet still available as a sexual partner for Fanny. Mary seeks to draw him over into the base side of love, and she nearly succeeds. Only her greed in wishing to secure a better income for him before she commits destroys her plan. Her brother's motives are closely aligned with hers, although it is not money he is after. His pursuit of Fanny will lead the plot into some morally ambiguous territory; the very same qualities that make wooing Fanny a challenge are the qualities that make her a worthy partner, and to many, Sir Thomas and Edmund included, Henry seems to be displaying his good taste and moral excellence, not his love of sport, in courting Fanny. She also promises to be a good influence on him; perhaps their marriage would be beneficial overall for its effects on his character, despite the damage to Fanny's happiness.
William, Edmund, and Henry are compared in another way, too: their choice of occupations. William's career at sea has made him a glamorous figure; he is brave, committed, and hard-working, but he has not yet been rewarded with a promotion. Edmund is also committed and will probably be hard-working as a parson; he, however, has the luxury of a wealthy family to ensure that he does not need to worry about money. His decision to take orders is as much a philosophical position as it is a career move; he doesn't need to live at Thornton Lacey and give the sermons himself, but he will. This highlights his essential incompatibility with Mary and angers her most. Henry, of course, has no career; he is a wealthy young heir. His daily "work" involves entertaining himself, and does not contribute to character formation in the way that Edmund's and William's livelihoods do/will. The choice of a career for the male characters in this novel parallels the choice of a husband for the female characters, as financial pressures often come into conflict with more noble considerations, and the proper choice is not always simple or obvious.
Regarding Maria Bertram and Mrs. Norris in the last chapter, neither leaves England. When Austen writes that "an establishment [is] being formed for them in another country," she does not mean continental Europe. Here, "country" simply means another part of the same country (most likely somewhere in the countryside). They are still in England.