Mansfield Park by Jane Austen Chapter 35 Page 11

probability of your happiness together: do not imagine it. I am myself convinced that it is rather a favourable circumstance. I am perfectly persuaded that the tempers had better be unlike: I mean unlike in the flow of the spirits, in the manners, in the inclination for much or little company, in the propensity to talk or to be silent, to be grave or to be gay. Some opposition here is, I am thoroughly convinced, friendly to matrimonial happiness. I exclude extremes, of course; and a very close resemblance in all those points would be the likeliest way to produce an extreme.

A counteraction, gentle and continual, is the best safeguard of manners and conduct.”

Full well could Fanny guess where his thoughts were now: Miss Crawford's power was all returning. He had been speaking of her