"Do you doubt that he'll find a way to make his fire hotter?"

"Do you doubt that I have described its capabilities accurately?"

"Do you doubt that the other portal will be there?"

And I would still doubt that 60% number in either case.

"Do they doubt that the ones in question are protected?"

"Do you doubt that I can see into your mind?"

"Though I doubt that those men would be so reckless."

I doubt that amounts to even 10 percent of the full budget.

"Never doubt that your father was always very proud of you."

"Do you doubt that she will make him a good wife?"