Lily, having spent the night at the Bellomont, is asked to join Mrs. Trenor in the morning to help her write some correspondence. Although Lily would rather not, she remembers that she is dependent on Mrs. Trenor for social standing and does not want to upset her. The two gossip extensively while they write dinner cards, providing the reader with information about the politics and current events of the social group. In particular, we learn that Gwen Van Osburgh was not entertained by the party, Alice Wetherall and her husband were invited by mistake, and that Maria Van Osburgh was infuriated because Mrs. Trenor's party "stole" guests from a party that she herself was throwing that week, including Lady Cressida Raith, an enormous bore and hypocrite whom Mrs. Trenor now dislikes. Bertha Dorset is also upset with Mrs. Trenor because she came to the party under the assumption that Selden would be present, and when he failed to attend, Bertha suspected that Mrs. Trenor had lied to her and not even invited Selden.
Lily confesses to Mrs. Trenor that she is interested in a marriage to Percy Gryce, largely because of his finances and good societal standing. We learn later that Lily believes that she will almost inevitably marry Gryce, thinking she has him under her control.
Later, Selden joins the party at the Bellomont, and after Lily goes to the library and finds Selden and Mrs. Dorset alone together, she suspects that Selden has really come to the Bellomont just to see Mrs. Dorset. Selden later confesses that he came solely because he wanted to see Lily. In the presence of Selden, Lily begins to examine her own social world and wishes that like Selden, she were detached from it.
The end of Chapter Five and all of Chapter Six focus on a walk that Lily and Selden take together after church ends on Sunday. They discuss a number of details about their lives and also share some of their philosophies on money, success and society. Selden says that he believes Lily is interested in Gryce, who left the Bellomont after Lily canceled their plans to go on a walk together (so that she could secretly spend time with Selden instead). We learn also that Lily has once before been in love several years before the action of the novel to a man named Herbert Melson, who ended up marrying the oldest Van Osburgh daughter.
Lily confesses to Selden that she knows her quest for better social status will not necessarily bring her true happiness. However, she and Selden agree that they will not marry one another. However, just as they are drifting towards what could be a confession of love for one another, they hear a car start its engine nearby, which reminds Lily that she must return to the Bellomont before people question her whereabouts.
The gossiping between Mrs. Trenor and Lily in Chapter Four provides the reader with some clues about the role of family in the society. Many of the female characters have been through at least one divorce; Mrs. Trenor mentions that between the Winton and Farley families there are "five divorces and six sets of children." This is Wharton's method of foreshadowing that The House of Mirth will not follow the conventional form of the novel of manners (see "The Novel of Manners" section), which normally does not feature divorces or broken homes. Because not all characters meet with happy endings, we begin to suspect that despite a relatively promising future, Lily also will fail in her attempts at securing happiness. The fact that Lily already failed once in love when she fell for Herbert Melson is another clue that Lily does not and will not meet with success in love.