Emma’s concern for Harriet fuels her anger with Frank and herself. She regrets having again mistakenly encouraged Harriet’s affections for a man. She also now understands Jane’s recent coldness towards her as motivated by jealousy. Emma is happy for Jane, and generously reflects that Jane will finally attain much deserved social and financial security with marriage.
Emma quickly puts the pieces together, and we see just how much she has grown in her selfless concern towards Harriet and regard for Jane. Despite her anger at the secret engagement, she acknowledges Jane’s merits and is happy for her future rise in fortune.
When Harriet arrives at Hartfield, however, it turns out she already knows about the engagement from Mr. Weston and is entirely unperturbed. Emma, surprised, soon discovers that Harriet’s interest has been in Mr. Knightley, not Frank, all along. Harriet informs Emma that but for her seeming encouragement, she would never have presumed to raise her eyes to Mr. Knightley. However, now she acknowledges hope of his reciprocal affection.
Harriet’s remarkable composure as she relates the true nature of her feelings shows how much she, too, has grown. She is no longer the agitated girl dependent on Emma’s opinion to make her own; she perceives Mr. Knightley’s merits and believes in her own. She does not ask Emma’s permission for the match.
Emma is upset. And from this distress, Emma realizes that she herself is love with Mr. Knightley. Out of a sense of justice to Harriet, she represses her feelings and inquires into the unfolding of Harriet’s. Harriet relates several moments in which Mr. Knightley displayed particular affection towards her—including the walk at Donwell—and Emma recalls similarly noting Mr. Knightley’s improved opinion of Harriet. Emma can only respond that Mr. Knightley would never intend to lead a woman on.
Emma’s forbearance and determination to be fair to her friend, to whom she has done so little real good, does her credit—particularly as it causes her great pain to hear Harriet recount signs of Mr. Knightley’s admiration for her. She also corroborates Harriet’s evidence with her own observations, showing a less fanciful judgment.
Emma is left to reflect on how very mistaken she has been about everyone: Frank, Jane, Harriet, and herself. She realizes that she has always loved Mr. Knightley; her love for Frank was a delusion. She regrets too her “insufferable vanity” in believing she knew everybody’s heart and could orchestrate their destiny. Now, she has only herself to blame for enabling Harriet and Mr. Knightley—a match that she reflects is not impossible, as the world has been revealed to be an “unequal, inconsistent, incongruous” place.
Emma reflects with horror and wonder upon the potential match between Harriet and Mr. Knightley. It is a match that horrifies her because of their great disparity in social class and wealth, but also inevitably because she is in love with Mr. Knightley. She finds, ironically, that she has become her own worst enemy, because of her blindness and vanity.