The main character, Isabella, is a very virtuous and chaste young woman who faces a difficult decision when her brother is sentenced to death for fornication (unlawful sex). Isabella does not approve of her brother's actions at all, but she pleads for his life out of loyalty and sisterly devotion. She is a spiritual person who starts off wanting to become a nun, however her decision to enter a convent is never explained. She is a character who seems to be indecisive as she doesn't really seem to know what she wants or who she is. It is as if Shakespeare is demanding the reader and audience to understand her more than Isabella understands herself.
Isabella is the main focal point of the play's sexual dynamic, as Angelo finds himself almost overwhelmed with her purity, and even the Duke proposes marriage to her. At the start of the play, Isabella is pictured as a completely non-sexual being, about to enter a nunnery and never speak to men again.
This adds a twist to her decision, as she is clearly not desirous of sexual intercourse when Angelo propositions her. Angelo is so taken with her that he cannot resist asking her to have intercourse with him, despite the laws he is enforcing in Vienna. Later, the Duke falls in love with Isabella as well.
Something about her is clearly very attractive to men. Lucio describes her as submissive and therefore very convincing. Perhaps it is her naive nature that attracts both men, who are obviously interested in power, given their government posts.
In act 2 scene 4, she is faced with the decision of sacrificing her virginity in order to save her brother. However, Isabella believes that sacrificing her virginity would be a sin, but she then claims that she would...