Money is something you have on your account. Everything else is your subjective judgement about the probability that the counter-party will pay you the money.
The same way the deal is something you have in written in the agreement. The rest is your assessment of the probability of the deal. Here is the question. How far should your commitment to something get before you have the formal agreement? When enough is enough? How many hours should be spent on the project before you formalized the relationship with the partner? Should you be committing with your money or resources before you are confident in the outcome? Moreover, can you ever be certain before the agreement is signed?
This question pops up over and over because it is the usual dilemma. You may not get a deal without upfront commitment and may increase the waste if you engage, and the deal won’t happen.
Even knowing all the fancy words like BATNA and Purple style of negotiations you have to take the risk. Each and every deal is still a bit of art, and prior failures will not save you from the future ones. You can at best minimize the failures probability or control the damage better.
I am writing this right after the critical negotiations failure. It is, however, the case when you have nothing to blame yourself for. You did everything right, and it just happened. Next time you will be doing the same thing in spite of the fact that doing it may lead to the failure. I learned the lesson, but it will not help.