Secondary Characters in Pride and Prejudice

I read the annotated version of Pride and Prejudice as well as watched the film from 2005.  One of the main things I noticed about the story was the difference in the treatment and endings between the main and secondary characters.  The Bennett household was not particularly wealthy or of a high status in comparison to the Bingley or Darcy households.  Mrs. Bennett pushes Jane and Elizabeth to get married so the family can be taken care of if something were to happen to Mr. Bennett.  Despite their lower social class, Jane and Elizabeth manage to win the hearts of Mr. Bingley and Mr. Darcy.  They have the opportunity to marry for love rather then circumstance.  Charlotte Lucas represents the more realistic situation for young women in the period.  She does not choose to marry Mr. Collins because of love, but as a way to live her life honorable.  On her engagement to Mr. Collins she says to Elizabeth: “‘I am not romantic, you know.  I never was.  I ask only a comfortable home; and considering Mr. Collins’s character, connections, and situation in life, I am convinced that my chance of happiness with him is as fair as most people can boast on entering the marriage state.'”(PP Ch.22)  Looking at the character of Anne De Bourgh, we do not learn that much about her except that she is sickly and has not been presented to society.  She was also betrothed to Darcy.  What can be made about her character?  Was it her destiny to live out her life as a spinster?  The freedom that the Bennett sisters have is much greater then most of the secondary female characters in the novel, they are able to break social norms.  Why did Austen create this juxtaposition between those sets of characters?

Image Source: https://www.pinterest.com/pin/108156828531539012/