One thing I've learned in my 61 years is to NOT count them chickens afore they hatch.
I've sold a bunch of cars and have 'shown' them even more till ya get that one individual who really wants it. Tire Kickers are part of the game. Outa 10 or 20 or 50 lookers all you need is that ONE.
Unless there was an exchange of monies, then ANYone has the right to 'back out' even after they spend time and money to come see your car.