There's a famous scene in the 1992 movie "A Few Good Men" where the hardened professional soldier (Jack Nicholson) yells to the idealist lawyer (Tom Cruise): "You can't handle the truth!"
Sad to say, that's often the case for salespeople, who are sometimes afraid to ask prospective customers questions that might reveal that the "opportunity" isn't going as well as they assumed.
If you really want to know the truth about an opportunity, you'll ask the following questions:
Any one of these questions has the potential to puncture the fantasy that they're close to making a sale. However--and excuse the cliches--unless you want to live in a fool's paradise, you'll ask the tough questions, and let the chips fall where they may.