There is an interesting dialogue in Chapter 5 between Henry and Mary Crawford. They have just met all of the Bertrams and have been talking about whether Maria loves Mr. Rushworth or not, and that poor Mr. Rushworth will be duped. Then Mary says a few interesting things:

“Oh dear! let him stand his chance and be taken in. It will do just as well. Everybody is taken in at some period or other.”

“Not always in marriage, dear Mary.”

“In marriage especially. With all due respect to such of the present company as chance to be married, my dear Mrs. Grant, there is not one in a hundred of either sex who is not taken in when they marry. Look where I will, I see that it is so; and I feel that it must be so, when I consider that it is, of all transactions, the one in which people expect most from others, and are least honest themselves.”

“Ah! You have been in a bad school for matrimony, in Hill Street.”

Somehow, it appears to me that Mary is quite bitter on the subject of marriage. The way she talks, nobody can ever be happy when married and everybody is "taken in". I wonder what bad experiences she's had to put her in such a mind-set. If this story were set in the present, I could picture her telling about some disappointing relationship from her recent past.