Well, in a 'true women novel', you'll usually find that the female characters are portrayed as morally upright. They are shown to be devout in their religious beliefs, which was a big part of the concept of 'true womanhood' back then. Their purity is not just in a physical sense but also in their thoughts and actions. For example, they might resist any improper advances in a very genteel way. And their submissiveness is seen in how they defer to male authority, like fathers or husbands. Their domesticity is a central aspect too, with a lot of emphasis on their role in running the household, taking care of children, and creating a harmonious home environment.
Well, to know if 'Women in Blue' is a true story, you'd have to look at the author's notes or research about its origin. Sometimes, stories are inspired by real-life incidents but have fictional elements added for drama.