The encounter between Hamlet and Gertrude that occurs in Act III scene 4 is of course a very dramatic scene. Gertrude has just scene her son openly insult her new husband, Hamlet's uncle, the King, by accusations that he killed her first husband. He also clearly rewrites the play to mock her own vows of constancy and love for the old King Hamlet. The stress that is placed upon this meeting is one of incipient violence. Gertrude fears that her son may murder her, and this causes Polonius to reveal himself, making Hamlet think it is Claudius behind the arras and causing him to kill Polonius by mistake. What follows is a violent diatribe delivered by Hamlet to his mother where he accuses her of giving in to the temptation of lust:
O shame, where is thy blush?
If thou canst mutine in a matron's bones,
To flaming youth let virtue be as wax
And melt in her own fire.
The stress of this encounter is therefore one of violence and anger, as demonstrated through Hamlet's killing of Polonius but also the angry and violent way he upbraids his mother, effectively calling her a whore because of how she gave in to her lust and was not able to remain constant to her first husband. The impact of this encounter is that it causes Gertrude to move away from Claudius and to recognise, at least in part, the truth of what Hamlet tells her. After he finishes his speech, she admits that his words make her look at herself and see an inner ugliness and inner faults that she had not been aware of.