Portia is the classic example of a Shakespearean heroine: witty, beautiful, and wealthy. The heir to her late father's fortune, she is a free spirit who openly rejects the rules and blazes her own path. Though her father set up a bizarre lottery to ensure his daughter marries, Portia is determined to make her own choices. She also possesses a stunning knowledge of the law, appearing in a courtroom disguised as a man while perfectly applying it. Her greatest weakness as a character is the fact that she is a woman in her society, but she refuses to let that stop her. Shakespeare makes it clear that Portia is much more than a beautiful woman with access to wealth; she is strong, resourceful, and intelligent.
Turning to Jessica, she is Shylock's only daughter and breaks his heart when she leaves him to marry Lorenzo, a Christian. Shylock seems quite cruel towards his daughter. Whenever they're onstage together, he's giving her orders and commands her to remain inside. Though we may understand why Jessica fled and eloped, she does seem cold at times. She trades her late mother's ring for a monkey after she elopes with Lorenzo.
Shakespearean women often have another woman by their side. For Juliet, it was her Nurse. Ophelia was Queen Gertrude's lady-in-waiting in Hamlet. Desdemona had Emilia. In The Merchant of Venice, Portia has Nerissa. Nerissa is highly respectful of Portia but also gives her quite a lot of tough love. She listens to Portia complain about her father's contest to win her hand, but ultimately tells her she should be thankful that her father has secured her future. She seems practical, especially when she agrees to marry Graziano so that Portia can marry Bassanio.
We have here a tale of three women: the brazen, beautiful Portia; the shrewd and rebellious Jessica; and the practical, quiet Nerissa. The women all have one thing in common: they're women working against the constraints of their society, although some are more willing to rebel than others. While each of the women faces her own challenges, they each react to them in different ways. Portia blatantly resists, Jessica is shrewd and disobedient, and Nerissa does what she can to help Portia.