He still isn't sure

This sentence was in an article describing how Iraqis are beginning to cooperate with American troops. I'm only interested in the syntax, here. It strikes me as very odd.

He still isn't sure that Sunni extremists aren't listening and that a casual chat with the colonel will be a death sentence.

It's perfectly grammatical, but if you deconstruct it into two separate sentences the second one sounds odd:

He still isn't sure that Sunni extremists aren't listening. He still isn't sure that a casual chat with the colonel will be a death sentence.

This is an example of undernegation. Yes, sometimes (very often in fact) you do want two negatives, and this is one of those times. The construction "he still isn't sure that" means that "he wants to be sure that..." That comes across naturally in the first sentence (he wants to be sure that Sunni extremists aren't listening) but the second? Just as the negative was required for "listening", it's required for "will be" - each clause needs its own.

He still isn't sure that Sunni extremists aren't listening and that a casual chat with the colonel won't be a death sentence.