The noun estimation refers to a judgment of the qualities of something or someone. In your estimation no boy will be good enough for your daughter. He could be the kindest and smartest person on the planet and you'd still find fault.
The noun estimation has its Latin roots in aestimare, meaning "to value." One of the definitions for estimation is an approximate calculation of something's value. If you go to an auction, you can often review a catalog that will have an estimation of the value of each item for sale. Sometimes the items sell for more than the estimation and sometimes less. The auctioneer hopes there are many bids for the pair of stone lions, but if you're bidding, you hope you're the only one who wants them.