Thats big of you to say, but I'll counter and declare that its unreasonable to request that someone hold something for you without a monetary gesture of intent.
I told Ron a couple months back that I was going to buy his truck, we didnt complete the transaction until last week. I'm sure he took me at my word that I would show up the the cash and I expected him to not sell the truck to someone in the interim.
Unless there is an existing relationship, then you're taking advantage of someone to request they not sell it to someone while you organize yourlself. Business needs to be kept professional - I always offer a deposit and when its not accepted, its usually appreciated.
If there is any criticism here, I would say that you shouldnt accept unreasonable requests so that you can get caught out by a disgruntled guy.