In sales, How do I verify that a done deal is in fact a done deal

Ask the following questions:

1.Once you’ve made the decision to buy, then what happens?
2.Who else has a stake in the decision or influences the outcome?
3.Is there anyone who needs to review this decision prior to payment?
4.Is there anyone who can veto this decision once it’s been made?
5.What needs to happen in order for payment to take place?
6.Is a purchase order required and, if so, how does it get generated?
7.How have you purchased similar offerings in the past?
8.What happened and how long did it take to execute on the decision?
9.Has budget been allocated and, if not, how does it get allocated?
10.Is there any way to accelerate execution once a decision has been made?