Diana shows poor judgement when she gets pregnant with a married man.
Diana is a saintly presence. She is endlessly patient and supportive of the other factory girls. She has worked at the factory for fifteen years, and she acts as teacher and mother to new girls. Lyddie finds her to be a source of support and friendship.
When Lyddie gets a new girl to train, Brigid, she has trouble at first. Lyddie likes to focus on herself and takes pride in being fast and efficient. Having a trainee just annoys her and she feels like the girl slows her down. Diana comes to the rescue and is calm and caring to the girl when Lyddie can’t be.
When Brigid has trouble with a knot, Lyddie shouts at her, irritated that she has not learned how to do it herself yet. Diana steps in to help them.
The girl burst into tears again, and before Lyddie could decide what to do with her, Diana was there, slapping off the loom. Burning with shame, Lyddie glanced over as Diana, without a quiver of impatience, helped the girl retrieve the broken ends and tie a weaver's knot. (Ch. 14)
Diana looks out for the girls in bigger ways too. She is part of an organization lobbying for a ten-hour workday. Lyddie doesn’t like this, because girls can get in trouble for signing the group’s petitions. The factory considers them trouble makers. Diana is more interested in everyone’s safety. She takes up collections when people get hurt or sick.
When Lyddie finally decides to sign one of Diana’s petitions, she learns that the saintly Diana has a secret. She has gotten pregnant, and the man is married. He is Diana’s friend the doctor.
"He‐he's not free to marry. There's a wife ... in Concord. She wouldn't come to live here in a factory town. Though her father is one of the owners." Diana's laugh was short and harsh. (Ch. 19)
Diana has to quit her factory job before she begins to show, because she doesn’t want to bring dishonor to the movement. She is such an important part of it that the factory would use her to discredit it. Diana is strong and independent. She finds a job as a housekeeper right away, and plans to raise her baby by herself.
Diana is a genuinely nice person, but having a baby out of wedlock was considered very immoral. She also had an affair with a married man, which is definitely inappropriate. This does not mean that Diana is a bad person, but she definitely exercised flawed judgement.