Angelo replies, "Who will believe thee, Isabel?" (II.iv.144). He speaks of his reputation and position in the state, suggesting that he has more power than she does. He tells her to be less timid and agree to his proposal, or else her brother will not only die but also suffer a long and painful death. He gives her until the next day to decide and leaves.
Isabella is left to think about the situation by herself. She wonders who would believe her if she were to tell what has happened. She decides to visit her brother, sure that he will agree that she should not give up her chastity for his life. She also hopes to put his mind at rest before he dies.Read a translation of Act II, Scene iv →
The very structure of this scene is frustrating. The audience is immediately aware of Angelo's intentions, but Isabella is either too naive to understand them or too desperate to avoid the actual proposition. She is obviously offended by the very notion of having sexual intercourse with Angelo, becoming furious at the suggestion. It may be her angry reluctance that makes her so desirable to Angelo. It would not be difficult for him to find a sexual partner, considering the prevalence of prostitution in Vienna, and later we discover that there is a woman readily available to him as a wife. He seeks to abstain from sexual activity, and only Isabella draws him out of this resolution.
Isabella is given apparent power over her brother's situation, and she genuinely believes that she could save her brother's life. She refuses the option instantly. In a way, she is handing this power over to God; her virtue and her soul are, for her, in God's hands, and by refusing to disobey his will she is only following along with his expectations of her. Her power is solely sexual, and so she refuses it. Although Isabella is fast in her determination to refuse, Angelo gives her a day to think about it. Dramatically, this gives Isabella time to discuss the proposal with her brother and the Duke time to formulate a plan. It also shows that Angelo believes she will relent with enough persuasion.
Two larger issues emerge in the exchange between Angelo and Isabella. Angelo brings up the topic of love, claiming to be in love with her. He does not promise to marry her, however, implying that he really feels solely lust. Isabella mentions that she would rather die than have intercourse with him, which becomes her primary justification for refusing. She formulates the opinion that death is favorable to shame, and decides that her brother's death is better than her own sinful act.