Nancy, like Silas, changes during the course of the story. However, her change is not the apparent result of the force of events. Rather, it is the realization of something that was inherent in her, a simple process of maturing. It is none the less believable for that.
Nancy as a young girl is charming and graceful. These qualities Eliot brings home by demonstration — by portrayal of her actions, by the testimony of other characters, and by narration. Nancy is also shown to have high and strict principles: she does not care to associate with any man of poor reputation. It might be feared that her principles will become too strict with time, except that her character already has the saving touch of emotion. Despite her resolves, she cannot entirely overcome her love for Godrey.
Part of Nancy's youthful "principle" is girlish self-dramatization. When this disappears with her maturity, it leaves a base of real principle, but it is sweetened by a love that can become sympathy. Nancy's principle keeps her from adopting a child, but her love for Godfrey makes her try to make it up to him in other ways. When she discovers that Eppie is Godfrey's own daughter, it is not the principle that governs her actions, as Godfrey had feared, but love and sympathy. The insight into her character that has been given through the scenes presented from her point of view has prepared for this development. It is a surprise only to Godfrey.