Usually this issue comes up in an over-heated real estate market. Sellers are reluctant to trust the buyers lender. I don't blame the seller. In the past, some mortgage brokers wrote worthless approval letters, and buyers were later deemed to be not qualified. It's the seller that suffers, losing a sale and other more qualified buyers that had presented purchase offers.
The seller wants to ascertain that a potential buyer's financial worth has been vetted by a trusted source; there are unscrupulous lenders who might "pre-approve" a buyer without truly qualifying the borrow's ability to take out a loan for the amount of the purchase. It is "insurance" the buyer can close on a loan for the amount agreed upon in the purchase and sale agreement.
You really should enlist the help of an agent who will help you navigate your home purchase. It is likely the largest purchase you will make in your life and you should hire a professional to facilitate the process. (You likely wouldn't represent yourself in a court room, but rather hire a professional, an attorney, to represent you.) There is no charge to a buyer in Washington State to hire representation, a buyer's agent's commission is paid by the seller and is negotiated at the time of the listing, not at the time of purchase.. It is important you have your own professional representative that advocates for your success and not for the benefit of the home seller.
Please don't hesitate to contact me directly if you have more questions (answers, of course, are free of charge :-) 206-501-7837 or email me phoebe@SheSellsSeattle.com and visit my website to view all Seattle area listings: http://www.SheSellsSeattle.com
I am happy to help if you need me!
For more tips on selling your home, go to