Desdemona stood by her beliefs at all costs. She lost her own life and got many people killed by standing by what she believed.
Desdemona started the play by defying the wishes of her father and running off with Othello. She manages to keep the affair a secret until after they are married. This prevents her father from stepping in and destroying the relationship. “I am hitherto your daughter. But here’s my husband, / And so much duty as my mother showed / to you, preferring you before her father, / so much I challenge that I profess / Due to the Moor my lord.”(1.3.184-187) She so graciously throws her marriage in her father’s face basically saying I’m his now and there’s nothing you can do about it. We find out later that this sends the father into depression and eventually he dies of a broken heart.
When Cassio is fired, Desdemona believes his innocence and stands by her belief by standing up for him. Unbeknownst to her, this helps Iago with his master plan of ruining everyone’s life. Iago uses Desdemona’s strong will against her by telling Othello lies about her. Standing up for her beliefs enables Iago to “prove” the affair and makes Othello fly into a rage.
She believes that Othello loves her and believes in her. When she senses something is wrong with him she dismisses it as “something sure of state” (3.4.137) and blindly stands by her belief that he loves her and trusts her.
“Devil” [He strikes her] (4.1.235). Othello hits Desdemona and in her mind she has done nothing wrong yet she knows he is angry with her and turns to leave with the excuse of not wanting to offend him. She is still steadfast in her belief of his true love for her.
Even with Othello’s terrible behaviors, Desdemona stands by her own love for him “that even his stubbornness, his cheeks, his frowns … Have grace and favor in them. (4.3.19-20).
In the end, Desdemona’s strong beliefs get her killed. She refuses to see the signs that Othello has flipped and stays in her bed vulnerable to him. She hangs out and let’s him tell her that he’s going to kill her then she lays there and let’s him do it.
After Othello believes she is dead and allows Emilia into the room, Desdemona speaks. She claims that Othello didn’t kill her, she did it herself. She is still standing up for her belief that he loves her and she made the right choice in marrying him.
If Desdemona acted like the women of the time were expected to act and didn’t stand up for what she believed in it would have saved a lot of lives.