In The Homesman (2014), Mary Bee (Hilary Swank) was the antithesis of a regular woman in 1850. She could plow, she could shoot, and she wasn’t afraid to take on duties that other men shied away from. But, the first and last times she speaks in the film, she’s proposing to a man who turns her down. All of her strong, macho actions throughout the core of the film are bookended by failed attempts to step into the traditional female lifestyle she couldn’t have. Being a dominant woman of character and and a genuinely good person weren’t enough. Though her propositions are poignant, there’s an urgency in her words. She knows she’s running out of time.
It’s relatively clear that her offer of marriage at the beginning of the film was to a fellow who she knew, but not that well, and not for a long time. When she proposed to George (Tommy Lee Jones), while it was another desperate act to slip into societal normalcy, the two of them had formed some sort of genuine connection on their voyage; yet he still denied her. Being denied by the likes of a societal drifter was the final stressor that Mary Bee could take. She asked George to lay with her so she would at least not die without knowing that comfort, then took her own life. People didn’t live nearly as long in 1850. At the age of 31, she was almost past her prime in a time when most women got married before exiting their teens. She was depressed, and she had lost hope that she would ever be able to marry.
The film didn't do a great job of showcasing the mental anguish that Mary Bee was obviously suffering. Though the act is supposed to come as a shock, it does even moreso when we couldn't visualize the anguish of the character. We get that there's an urgency in her desire to find a husband, but not to the level that it goes. Since she was so dedicated to her commitment to transporting the women, she gave the impression that commitment would outweigh her personal issues. Still, it’s fair to infer the cause of her suicide from the film’s context.