...escape discredit and misery."

"I know that you could be neither happy nor respectable unless you truly esteemed your husband."

Hmm, that's pretty strong! The misery I can certainly see, but Mr. Bennet is also saying that if Elizabeth didn't respect her husband, she wouldn't just grin and bear it like Charlotte or Jane, but would probably do something that would bring "discredit" on her in the eyes of society! I wonder what he's picturing...