I have only seen at least two sketches of the actual Jane Austen, and for me i think she doesn't look half bad. Really i don't think we can count on a old painting/drawing to give justice to a person back then or even further. I know i have seen some drawings of Shakespeare and when i read his pieces i would not have guessed that he would look like the way he is depicted, not very romantic. But i suppose that most paintings were not expertly done and he was a lot older then. And then their are a lot of other authors who look very different than what i would have guessed, all i am saying is that Jane Austen looks pretty good for being drawn out.
In a lot of European paintings the person has a full and round jaw and chin, it makes them all look the same.