The lady protests too much, methinks.
Act III, Scene 2 · Gertrude
Context
After watching the Player Queen's extravagant vows never to remarry, Gertrude comments that the lady is protesting too much.
Analysis
Gertrude's word choice—'protests' (vows, but also objects)—captures the excessiveness of the Player Queen's rhetoric, yet it also inadvertently confesses her own guilt: if extreme vows are untrustworthy, then Gertrude is admitting she never meant her own marriage vows seriously. The phrase has become proverbial precisely because it is self-incriminating—Gertrude reveals more than she intends, making this one of the play's great moments of unconscious irony.
Essay Tip
Support a thesis that Gertrude's language constantly betrays her even when she tries to seem innocent—this line exposes her skepticism toward marital vows in general, revealing why her remarriage came so easily.