What is the main conflict in Redeeming Love by Francine Rivers?

Redeeming Love is based on the Biblical chapter of Hosea, in which God tells his prophet, Hosea, to marry the prostitute, Gomer, to illustrate God's faithfulness to Israel despite Israel's sin. The novel is set in the nineteenth century, and told mostly from the perspective of the prostitute, Angel. Her birth name is Sarah, but she hasn't told anyone her name since being sold into prostitution at the age of eight.