We learn about a character that the title simply calls "The Tale-Teller," who is androgynous (because she passed for a boy), and who is from a unique point of view (her very presence is an argument for religious tolerance, because her stories are fascinating at least in part because of her Jewish background). Esther's namesake is from the book of Esther, another story where a young Jewish girl is isolated from her community because of marriage. But, this story features Esther not for her character traits but for her point of view.
Therefore, the suggestion of the plot is that Esther's point of view is important. Notice that since she had to hide her gender and religion, those are the parts of her point of view that are considered intolerable in her community. But, when she speaks, she is beautiful and poetic, and her stories are compelling. When they call on her to explain herself, why she has been deceptive, she explains that it was because of the enormous slavery that was placed on her.
The slavery wasn't slavery in Egypt. It was slavery to some random guy in Amsterdam who ordered her from her parents like a mail-order bride, just because she was a girl, and in her community, there is a saying that every Jewish daughter shall be married. So, she went her own way. In the context of her new community, that still seems to be her problem, which is an indication that the meaning of the novel is at least in part that there should be equal treatment of women, and that they should not be traded as property through marriage.
