Who is Anne Sharp from Jane Austen's Letters and what is their importance?

Anne Sharp was Fanny Knight's governess during the early 1800s. She was Jane Austen's friend, and she visited Chawton in June 1815 and again in August and September of 1820. Sharp rated "Mansfield Park" as an excellent novel, but she preferred "Pride and Prejudice", ranking "Emma" somewhere in between.