The Duchess begins the story as a prostitute who is ejected from Poker Flat along with her pimp, Mother Shipton. As such, she is crude and garish, obviously having been corrupted in life. However, what transforms her and other characters is the arrival of Tom Simson with Piney Woods, who both of them, in their naivety, do not realise the kind of backgrounds that the Duchess and Mother Shipton come from, and thus treat them as equals with love and respect. The effect of this is staggering. Note how, from Piney's first conversation to the Duchess, there is a change that is registered:
Piney was actually talking in an impulsive girlish fashion to the Duchess, who was listening with an interest and animation she had not shown for many days.
The love and the care that the Duchess begins to feel towards Piney is what transforms her from a prostitute to being just as innocent and sinless as Piney herself. Note the touching and rather poignant discovery that is made of their bodies, which embrace each other, after their deaths:
And when the pitying fingers brushed the snow from their wan faces, you could scarcely have told from the equal peace that dwelt upon them which was she that had sinned.
The character of the Duchess, among others, is one example of how natures can be transformed and innocence and love, when freely offered, can impact even the hardest heart.