Nearly every Jane Austen heroe, about the final proposal and acceptance, undervaluates him/herself and overrates his/her future wife/husband.
You find there flattery; but for instance, Mr Knightley cannot flatter, this is even his most wonderful characteristic to me : being able to be so violently in love, to have lost part of his abilities without having lost his "upright justice" that makes him reproach Emma her mischief to Miss Bates exactly as he ought to, venturing her love for him (and it is the main common point with Balzac's La Brière in Modeste Mignon); yet he speaks of Emma as "this sweetest and best of all creatures, faultless in spite of all her faults" (chapter 49), "I am losing all my bitterness against spoilt children, my dearest Emma. I, who am owing all my happiness to you, would not it be horrible ingratitude in me to be severe on them?" (chapter 53) "Nature gave you understanding:—Miss Taylor gave you principles. You must have done well. My interference was quite as likely to do harm as good. It was very natural for you to say, what right has he to lecture me?—and I am afraid very natural for you to feel that it was done in a disagreeable manner. I do not believe I did you any good. The good was all to myself, by making you an object of the tenderest affection to me." (chapter 53) - that is, he is blind in no way but overrates her merits and underrates his own. As does Emma, giving way maybe to more dislike of her, among readers, than she deserves?
So do Pride and Prejudice heroes, in my opinion, and I find there a process inside love, that reverts the tendency of overrating th others' mischiefs and underrating oneselve's, which is a great help indeed, in the first period of marriage, when so much is to be borne by each newly wed just by common life, that it could spoil their happiness, wouldn't there be this tendancy.
A recent survey tells it in other words (link below).