I am testing whether "A wants B to guess..." can be followed by both declarative and interrogative clauses. I am not a native speaker but "A wants B to guess that.." does not sound acceptable to me.
Do you think they are natural sentences in English?
[1a] Mary wants Sue to guess who John talked to.
(This should be perfectly natural, right?)
[1b] Mary wants Sue to guess that John talked to Prof. Smith.
(If this sounds natural, how do you interpret this sentence?)
As a contrast, compared with 1b, what do you think about
[1c] Mary wants to guess that John talked to Prof. Smith.
(Is 1b better than 1c?)