Suppose that you were running for President.
In the audience are a few birthers, one of them pops the question "Do you think Obama was born in the US?"
(Do you ignore this voter(s) and brush him off?)
If you answer "yes" someone will invariably follow up with "What make you believe that?" You'll have to qualify your answer with "I read it on the net, someone told me, I believe whatever the gov't tells me is true".
Or
You can say, "I personally checked into this and the evidence has satisfied me".