The character of Sarah Woodruff is fascinating in the way that she is described as an enigmatic figure who never really is conclusively explored or explained comprehensively by the author. One of the interesting aspects of the narration is that the author deliberately witholds a full description of her character throughout the entire novel, and some critics see this as a sign that it is impossible to know another person completely and that there will always be the presence of some mystery as the understanding of humans is reliant on individual perspective rather than objective truths.
Sarah therefore does seem to exist more as a symbol rather than an independent character in her own right. It is obvious that she is juxtaposed with Ernestina, who is meant to be the perfect Victorian woman. Sarah, by contrast, deliberately shuns the expectations of society and chooses to live a life free from the restrictions of her time and culture. It is this that draws Charles to her as this quote makes clear:
He said it to himself: It is the stupidest thing, but that girl attracts me. It seemed clear to him that it was not Sarah in herself who attracted him--how could she, he was betrothed--but some emotion, some possibility she symbolized. She made him aware of a deprivation. His future had always seemed to him of vast potential; and now suddenly it was a fixed voyage to a known place. She had reminded him of that.
This quote highlights the way in which Sarah exists more as a symbol than as a real person, as it states how she "symbolised" a possibility and "made him aware of a deprivation." Sarah is defined by her status as outcast, highlighted by her background, where she was born working class but educated as if she were a middle class girl, and then by her refusal to bow to the subservient role that Victorian society tries to place on her. This is something that echoes deep within Charles and causes him to reject the future that society has planned for him. Sarah's character therefore deliberately remains enigmatic throughout the entire novel as we see her through the male gaze of the narrator and of Charles, thus leading to the conclusion that she exists more as a symbol than a real individual.