Please help with a paraphrase.How can I change this into my own words? I've been playing around with it, but i can't figure out how to make it...

I think that you have a very strong starting point here. 
It seems to me that you might want to lay off the colon use and just word it to be a bit
more direct in what you are trying to say.  Something that popped into my mind would be
that "In his short story, A Lady's Beaded Bag, Tennessee Williams
argues that a part of human nature is the social classification of people on the basis
of wealth."  A similar way to approach this would be to bring out the "class system" in
the thesis statement.  I would say away from the idea of "hope, desperateness [sic] and
opportunity" because I think these are going to be brought out in the body of the
writing piece.  Williams is a writer who is able to bring out the social dimensions of
people's interaction in class systems or other forms of stratification, and when this is
brought out, I think that the emotions that are alluded to in the first part of the
thesis statement would become evident.