In Act 3, Scene 2 of Hamlet, the Queen says, “The lady doth protests too much, methinks.” Why is her claim ironic?
When Gertrude says these words, she has just watched the scene from The Mousetrap, the play that Hamlet has rewritten parts of in order to observe Claudius and get him to reveal his conscience, where the Player Queen and Player King have been discussing the fact that he will die soon, and the Player Queen will remarry.
The Player Queen insists that she would never remarry, that no one could ever take the place of her current husband. She says that kissing another husband in bed would be like killing her first husband twice. She swears her undying loyalty to her first husband even after he dies. When the Player King says she will change her mind after he is gone, she strongly protests saying:
Nor earth to me give food, nor heaven light!
Sport and repose lock from me day and night!
To desperation turn my trust and hope!
An anchor's cheer in prison be my scope!
Each opposite that blanks the face of joy
Meet what I would have well, and it destroy!
Both here and hence pursue me lasting strife,
If, once a widow, ever I be wife!
Of course, Queen Gertrude married Claudius within a month of her first husband's death/murder. So when Hamlet asks her how she likes the play, she realizes how similar the circumstances in the play are to her own life and how she did not remain loyal to Old Hamlet. So she declares that the Player Queen is making too big a fuss about remarriage.
Check out the great side-by-side text of Hamlet at the link below to help you understand the play.