Lady Lucas
Pride and Prejudice Jane Austen

Lady Lucas is the sister to Mrs. Bennett, the "mother" in the series. Lady Lucas has one daughter - Charlotte Lucas - who is Elizabeth's best friend. They are cousins. Poor Charlotte is 28 and still not married, because she is rather plain. Charlotte just wants any marriage so she can get out of the house. Lady Lucas is of high class for the area, but is frustrated that her daughter is destined to become a spinster.

Lady Lucas
Lady Lucas in the BBC Miniseries

Pride and Prejudice