1. Soliloquy in Act III, Scene III: In this soliloquy, the King expresses his guilt and acknowledges the gravity of his actions. He says, "O, my offense is rank, it smells to heaven; / It hath the primal eldest curse upon 't, / A brother's murder. Pray can I not?..." He is aware that his crime is heinous and that it carries a heavy burden.
2. Conversation with Hamlet in Act III, Scene IV: When Hamlet confronts the King about his crime, the King reacts with guilt and remorse. He admits to his actions and expresses his regret. He says, "O Hamlet, what a falling-off was there! / From me, whose love was of that dignity / That it went hand in hand even with the vow / I made to her in marriage..." The King acknowledges that he has fallen from grace and deeply regrets his betrayal.
3. Attempt to Pray in Act III, Scene III: The King tries to pray for forgiveness, but he finds himself unable to do so. He feels that his crime is so great that it cannot be forgiven. This reflects his internal struggle with guilt and remorse.
Throughout the play, the King shows signs of remorse and regret, indicating that he is not entirely devoid of conscience.