Your sales interview mindset.
Some points to think about, believe in and one-way or another convey to your prospect:

I'm not going to pretend that I don't want to make money.
I'm going to respect your need to understand my value and feel satisfied with any decision you make.
No question or answer is off the table - only through an honest dialog can we determine what comes next.
I will absolutely take "NO" for an answer.
If the answer is not an absolute "no" then lets save everyone some time and have a definable, scheduled next-step. (no chasing each other).

Of course - everyone is still going to lie! But a little honesty can go a long way toward helping you qualify your prospect and either move them through your sales process or cut them loose and move on to a new prospect and greener pastures.

-Rob Torre