Adding to the above, not taking away from it, or in opposition to it...
I can't imagine a question too hard for little one to ask. Now, that's from my view, not hers. What could be so hard to ask? (That is NOT indended to make fun of or belittle the original question!) Both she and I know we will ALWAYS get a frank, honest answer from the other. It is the most fundamental basis of our existence.
She may not like the answer.
Hell, I may not like the answer.
But the sooner it is in the open, the sooner I can go about making conditions allow the answer to be just as truthful, but one we can at least live with, if not like.