On the whole, Stella's quite a weak and passive woman, which is why she becomes a pawn in the epic battle of wills between her sister and husband. Caught in the middle of this titanic struggle over her soul, Stella can only do her best to provide a bridge between Blanche and Stanley. That in itself invites pity. No one would really envy someone in Stella's position.

But Stella isn't just caught between Stanley and Blanche. She's also caught between her love and desire for Stanley and the recognition that he's a violent, uncouth brute who really isn't ideal husband material. On an intellectual level, Stella must know that Stanley's not right for her. Yet because she loves him, and because she's attracted to his raw, overpowering sexuality, she remains right where she is: by his side. Stella's about to give birth to Stanley's child, which will keep her even more tied down to the bad relationship. To an outside observer, their union looks like the classic example of an abusive marriage.

Whether Stella realizes it or not, she is trapped. After Blanche is dispatched to a mental hospital, one senses that Stella's last chance at breaking free from Stanley has gone with her. That in itself is enough to invite pity.