“What is the most you would pay if you had to?” would be along the following lines: “Let’s not put ourselves under such a strong temptation to mislead. If you think no agreement is possible, and that we may be wasting our time, perhaps we could disclose our thinking to some trustworthy third party, who can then tell us whether there is a zone of potential agreement.” In this way it is possible to behave with full candor about information that is not being disclosed.
