I once sold a 30 year old car over the phone sight unseen by telling the guy every problem and issue and bit of history about the car without any hesitation. 

He immediately ***knew*** I was telling him the truth because much of it was super inconvenient, and he instantly purchased it and paid $1500 just to have the car shipped across the country.

I paid $800 for the car and sold it for $5k (not including shipping).  

k00b

First draft of my "Why you shouldn't use Stacker News" TABConf slide deck 

What if he answered, "because I want you to know the truth before you make an important purchase"

> But right away he starts showing you a list of all the problems of his house.

All great salesman know sales are about building trust. When you reveal an inconvenient truth, it sets a ceiling on what you're willing to lie about. 

Eg if I start by telling you this house needs a new roof in a year, when I tell you the air conditioner was recently replaced you believe me.

And when you tell all inconvenient truths ...