Sissy is by far the kindest and most compassionate of all the characters in the novel, and the person everyone calls when they have a problem. Sissy comforts Johnny much like a mother comforts her child when he goes though severe alcohol withdrawal, and when Willy Flittman is rejected from military service and goes to bed, refusing to get up ever again, Sissy is called in. She has him out of bed and pumped up to work at a munitions factory in no time at all. Sissy is a great listener who really understands people.
Francie simply loves her. Sissy often comes over to play with the children, bringing them little treats and checking on them while their parents work. Sissy is always kind.
If Sissy is so kind and compassionate, though, then why do so many people think she is bad? Her flaw is being unable to limit the amount of love she gives, and while people admire this when it comes to helping folks out, they're pretty judgmental about it when it comes to Sissy's fondness for men. She marries three times, has countless lovers between husbands, and technically ends up married to more than one man at a time to boot… which is kind of illegal and definitely frowned upon at the turn of the twentieth century.
More than anything, Sissy wants to be a mother. Her heart is broken ten times by the birth of stillborn children, but Sissy is convinced that she might have a chance to have a living child if she marries another man. In the end, we see her settled down with Steve, happy in the role of wife and mother.
But Francie misses the old Sissy—the one who wore too much perfume, strutted her stuff around, and always noticed hot guys in uniforms. The fact that Francie misses the old Sissy might mean that this isn’t a story about how Sissy is saved from her former bad ways. Instead, while Sissy has definitely changed, new Sissy isn't better than old Sissy.
Sissy isn’t perfect by any means. She mysteriously names all of her lovers and husbands John, which could lead us to believe she is secretly in love with her sister’s husband. She uses her feminine wiles to pretty much get what she wants from her men—all these guys are wrapped around her little finger, and the girl really knows how to work it.
She doesn’t always show the best judgment. She tricks her third husband into adopting a child by faking a pregnancy, and she leaves a box of condoms with Francie and Neeley one day, which leads to a big scandal. Plus, she takes a tricycle that isn’t being used to give the kids a ride around the block. When a police officer talks to her, though, she doesn’t get in trouble because he lusts after her.
Sissy is the least educated of the Rommely sisters. Her parents were too new to the country to understand that there was free education available, and by the time they figured this out, it was too late for Sissy to go. But in some ways, the least educated sister is also the one who seems to be the most connected to progress.
She does not feel limited by the society’s rigid expectations for women’s sexuality. To emphasize this further, she even works at a condom factory at a time when that is simply scandalous. Sissy divorces her husbands at a time when divorce was not as widely accepted as it is today, and she boldly breaks from the tradition of giving birth at home to have her eleventh baby in the hospital—a decision that winds up saving her baby's life.
In short, Sissy is a big bag of contradictions. She is so good to her family yet labeled a bad girl; she is uneducated and yet ahead of her time. Like most people, Sissy isn't easily defined.