"It is a truth universally acknowledged that a young man in possession of a fortune must be in want of a wife?I want make a speech of this
I suppose it would depend on what kind of speech you would want to make about this? Do you want to give a commentary on the way British upper middle class society worked in the early 1800's? Or do you want to make a commentary on how this is still true today in America?
If you want to make a speech about this about today's society, you could reference "The Real Housewives of. . . " Bravo series, you could reference statistics on how much more successful a wealthy man is if he's married in fields such as upper business management, politics, etc. You could also look into the psychology of why women want to marry wealthy men from a biological/psychological stand point as well as why a man who is wealth wants to be married.
Hope that helps! Next time you may want to be a little more specific in your question so we can better assist you. :)
I have a little different take on the statesment. During the time that "Pride and Prejudice" was written, the laws were all in favor of the man. If a man had gained wealth, he needed a wife to provide social representation and organize parties, etc. However, more important than that was the need to have a male heir. Without an heir the money one accumulated would go to other male relatives or the state. Therefore, it was important to have a wife. In addition, the laws often disallowed the transfer of an estate to illegitimate children so just having a mistress or girlfriend would not do in terms of passing one's fortune down.