Harriet arrives at Hartfield flustered and pleased; she has received a marriage proposal from Mr. Martin by letter and come to seek Emma’s advice. Emma is surprised by how well-written the letter is and somewhat snidely supposes that one of Mr. Martin’s sisters helped him write it.
Harriet reveals the extent of her dependency on Emma’s judgment, which further reinforces Emma's vanity. Meanwhile, Emma more deeply reveals the extent of her biases against the farmer class to which Mr. Martin belongs.
Emma behaves as though it is a given that Harriet will reject Mr. Martin and advises her to decline him promptly, unequivocally, and gratefully. When Harriet reveals that he is uncertain about her feelings towards her suitor, Emma feigns surprise. She at first declares she will not influence a decision that Harriet must make for herself, but then eventually starts gently guiding her friend to consider those candidates she considers to be more eligible.
Despite her ostensibly good intentions and affection for her friend, Emma will not allow her friend to make her own decisions about what will make her happiest. Instead, Emma cannot stop herself from manipulating Harriet into adopting her—Emma's—own preferences.
Harriet rather uncertainly suggests that she will reject Mr. Martin; Emma immediately applauds her decision, and she declares that if Harriet had married him they would no longer be able to be friends. Harriet is horrified at the prospect that she could have lost Emma’s friendship.
Emma’s support and friendship is revealed to be conditional upon her friend following Emma’s own opinions, as she makes it clear that they could not have been friends if Harriet had chosen to marry Mr. Martin, a farmer.
The two rejoice over Harriet’s narrow escape, though Harriet continues to defend Mr. Martin’s amiability and goodness. Emma then proceeds to guide every sentence of Harriet’s reply letter, even as Emma insists that her assistance is unnecessary.
Harriet’s loyal but somewhat blind following of Emma reveals both her weak will and the basis of their friendship in inequality: it works only so long as Harriet remains subservient to Emma’s will.
Emma congratulates herself on saving Harriet, though the latter remains somewhat despondent over the entire affair. However, Emma cheers her friend by reminding her of Mr. Elton’s warm regard.
Emma’s self-assurance that she has done right, despite her friend’s unhappiness, is rooted in her belief in the superiority of her judgment and feelings.