“This man is almost too gallant to be in love,” thought Emma. “I should say so, but that I suppose there may be a hundred different ways of being in love. He is an excellent young man, and will suit Harriet exactly; it will be an ‘Exactly so,’ as he says himself; but he does sigh and languish, and study for compliments rather more than I could endure as a principal. I come in for a pretty good share as a second. But it is his gratitude on Harriet’s account.”
– Jane Austen
Emma, Chapter 6. Mr. Elton offers to ride to London to have the picture of Harriet that was painted by Emma framed. In this passage we have Emma’s very happy but way off the mark thoughts. She thinks, wrongly, that his gesture is an expression of his love for Harriet. But it is actually Emma that he wants, as the reader is already aware of, an example of dramatic irony.