After Emma learns that Jane and Frank have been secretly engaged all along, we read:
"“Well,” said Emma, “I suppose we shall gradually grow reconciled to the idea, and I wish them very happy. But I shall always think it a very abominable sort of proceeding. What has it been but a system of hypocrisy and deceit, espionage, and treachery? To come among us with professions of openness and simplicity; and such a league in secret to judge us all! Here have we been, the whole winter and spring, completely duped, fancying ourselves all on an equal footing of truth and honour, with two people in the midst of us who may have been carrying round, comparing and sitting in judgment on sentiments and words that were never meant for both to hear. They must take the consequence, if they have heard each other spoken of in a way not perfectly agreeable!”
As a quintessential example of the irony that suffuses every word of this novel Emma, the pantheon of irony, we have, above, Emma working herself up to a hyperbolic indignant frenzy over the hypocrisy, deceit, espionage, treachery, over the judging, duping, dishonourable, secret league (those are all her own words, squeezed into those few sentences) composed of those wrongdoers, Jane and Frank.
And the irony, fittingly and typically, is unwittingly revealed by Emma herself--what bothers her most about all of these nefarious intrigues is not any genuine harms which may have resulted therefrom, but that Emma has been gossiping maliciously to Frank about Jane for over half the novel, and now Emma is horrified imagining that Frank has been passing Emma's speculations about Jane's love life right back to Jane all along. Not quite as bad as Emma's horrified suspicion that Harriet has had her sights set on Knightley, and that he has returned her affections, but still....pretty darned embarrassing! Emma cannot bring herself to turn the spotlight where it belongs, i.e., on herself, and to come to the explicit realization that she, herself, is the most tiresome, wretched gossip in all of Highbury!
But the richest irony is that I don't believe Frank has actually passed _any_ of Emma's whispered malice along to Jane in the first place--so Emma need not have worried!
The Aristocracy in the Seventh and Eighth Centuries
11 hours ago