Robert Chiltern sticks by his priciples winning the letter he sent to the baron for Arthur Goring. Robert and Gertrude kiss and make up, Arthur marries Mabel (Robert's sister) and they all live happily ever after.
Gertrude: Oh, Arthur... what a good friend you are to him, to us.
Lord Arthur Goring: Yes, but we're not out of danger yet. In fact, I believe there's a rather popular saying about frying pans and fires, except now it is you and I, dear Gertrude, who are to be roasted.
Trivia: The play that all are watching when Lord Goring fools around with his looking glass and Gertrude asks Robert what his business with Mrs. Cheevley is, is "The Importance Of Being Earnest" by Oscar Wilde. In the end you see the author coming out on the stage and saying a few funny words. This really occurred at the premier, Oscar Wilde did really say these things. It is a kind of play in a play, as "An Ideal Husband" was also written by Wilde.