When people communicate and they are uncomfortable with what they're saying, it's pretty easy to tell. It's not always a matter of dishonesty - sometimes it's more a matter of "I'm going to say this, I'm not really sure about it, and I don't know too much about it, but here goes."
In this one minute video, see if you can pick out the exact point at which Hillary starts to feel uncomfortable ("ums", eyes moving around, voice moving down in volume, etc).
And isn't it amazing that the Secretary of State of the U.S., third in succession to the highest office in the land, is talking about . . . well, you'll see.