Lady Bracknell : “I do not approve of anything that tampers with natural ignorance. Ignorance is like a delicate exotic fruit; touch it and the bloom is gone.”  

Lady Bracknell says this when she is interviewing Jack as a potential suitor for Gwendolyn.

Gwendolyn Fairfax: “If you are not too long, I will wait here for you all my life.”

After hearing the story about Miss Prism losing the handbag with a baby in it. Jack tells the women he must go up to his room for a minute. He asks Gwendolyn to wait for him and this quote is her response.

Jack Worthing: “It is a terrible thing for a man to find out suddenly that all his life he has been speaking nothing but the truth. Can you forgive me?”

Jack apologizes to Gwendolyn for lying about his identity when he realizes that, in fact, he had been telling the truth all along.  

Cecily Cardew: “Oh, I don’t think I would care to catch a sensible man. I shouldn’t know what to talk to him about.”  

Cecily tells this to Algernon after she catches him flirting with her and he tells her that a sensible man could get caught in her good looks.

Algernon Moncrieff: “The truth is rarely pure and never simple. Modern life would be very tedious if it were either, and modern literature a complete impossibility!”

Algernon says this in response to the knowledge that Jack does not actually have a younger brother named Ernest. Jack uses the fictious brother as a way to “escape” his life as a guardian to Cecily and have a little fun.