The famous quote from Queen Gertrude in "Hamlet" are her words "The lady doth protest too much, methinks." This is her response to Hamlet when he asks her how she likes the play that he arranged to incriminate Claudius for his father's death.
These words are from Act 3, Scene 2. Hamlet, believing that Claudius is guilty, wants to see his reaction. His mother's statement is one of the oft-quoted, or misquoted, lines from the entire play. The common saying that originated from these lines is "Methinks the lady doth protest too much." Queen Gertrude says these words because the play also incriminates her for remarrying so quickly. The modern use communicates the idea that when someone protests too much, he must have something to hide.