] It was a done deal, in her estimation. What is surprising is that she should so completely discount their own "difference of fortune". But that is because she is of the "sensibility" type, and all roadblocks to the union are not part of her thinking. Isn't this particularly unusual in these times? Times when so much stress was placed on what finances the woman came with? I guess not - if you are like Mom and Marianne.

Yes, it does seem an unwise for Mrs. Dashwood to ignore the financial differences, but her own experience supports her sensibility and views. She married Henry Dashwood and as per the second paragraph of Chapter 1, she brought nothing into the match. It makes sense that Mrs. Dashwood would think that if she could marry well with nothing, why couldn't her daughters.