When a buyer asks, "Why are you selling this?" the correct answer is none of your F**KING business.
What is a good answer to that question? My family is broke and I need money? I'm dying and have to sell stuff so the wife isn't stuck with it? The game is boring as can be?
People need to look at the item and then decide if they want it for that price. Nothing else matters but it is important to be honest and disclose any problems or flaws.