By the time we get to the end of chapter nineteen, we know Sarah's bitter isolation in her everlasting role of fallen woman is actually a choice motivated by her unyielding rejection of the only legitimate social roles available to her, of their low status and wealth and narrow cultural prospects.
In chapter twenty, she tells her tale to Charles, reinforcing that perception and painting herself as having quite freely and knowingly given herself to the French officer, Varguennes, though fully aware they would not have, and he never intended, a future together.
This is supposed to be a frank account of her notorious fall.
What Charles does not discover until much later is that she is lying and remains a virgin.
But what is the actual scope of her lies?
Did she even actually run off to join the Frenchman briefly in Weymouth, the alleged scene of her alleged fall?
As no one can bear witness any relationship at all developed between her and the officer while he recovered from his shipwreck at the Talbots', was there in reality any such thing?
Reading The French Lieutenant's Woman.