Just before this passage, we are told that Anne's impression of Mr. Elliot is "a sensible man, and he had looked like a *very* sensible man". In JA's world, a sensible man would inevitably discover his wife's true character in time, so are we looking at another Mr. Bennet here, disillusioned by his wife within a couple of years of the wedding? The only trouble would be that *this* potential Mrs. Bennet is not only silly and irritable, but also thoroughly selfish with a real mean streak. IMO, what Anne is hoping here is that Mr. Elliot's obliviousness will hold out just long enough to get him safely married to Elizabeth, so he can't back out! After that, she doesn't care what happens. You have a point, though, Jenny Allan, that it would probably be unnatural even for Anne to be too saintly in this situation! I totally agree with Lauren G that the thought of living with a disappointed Elizabeth is enough to make even Anne throw other considerations to the wind! ;-)