I believe the first part of the paragraph sets up the punch line you quote:

Mr. Bennet treated the matter differently. "So, Lizzy," said he one day, "your sister is crossed in love, I find. I congratulate her. Next to being married, a girl likes to be crossed in love a little now and then. It is something to think of, and gives her a sort of distinction among her companions. When is your turn to come? You will hardly bear to be long outdone by Jane. Now is your time. Here are officers enough at Meryton to disappoint all the young ladies in the country. Let Wickham be your man. He is a pleasant fellow, and would jilt you creditably."

And Lizzy, knowing he is teasing, responds in kind:

"Thank you, sir, but a less agreeable man would satisfy me. We must not all expect Jane's good fortune."