You ask him this:
Do you believe the government always tells the truth?
And you have him.
You can not believe the government isnt always honest and then choose that you believe them regarding a certain subject. If they lie on some things, why could they not lie about this?
On the same note, do people(humans) not lie and do things for their own reasons? Is the government not made of people?
Why is it that people in the government are somehow more honest than any random person on the street? The point is that they are not, so why believe them?
To climb the mountain, you must believe you can.