The phrase "already doubt that" is correct and usable in written English.
It can be used when expressing a pre-existing skepticism or uncertainty about a particular statement or situation.
Example: "I already doubt that the project will be completed on time given the current delays."
Alternatives: "have doubts about" or "question whether".
Some major leaguers had already expressed doubt that Wells was telling the truth.
Cashman has already expressed doubt that he will make a major trade, and even bad news regarding Gardner probably would not change alter his outlook, as long as teams continue to ask for top prospect) in trade talks.
There is already no doubt that NF-κB activation and translocation from the cytoplasm to the nucleus is a necessary and probably sufficient condition for the survival of the cell subjected to stress, as NF-κB mediates the production of a number of cellular inhibitors of stress-mediated apoptosis (Mattson & Meffert, 2006).
Emperor's Choice and Mountainous, the most recent winners of the race, have already proved beyond doubt that they have what it takes.
Whatever Chilcot concludes about the UK intelligence services, however, and about MI6 in particular, it should already be beyond doubt that the UK has little reason to boast of its superior coordination vis a vis its EU partners, and – without more honesty about our own use of extra-legal practices and excesses – still less of a case for national pride.
Cristina Bonilla, a 23-year-old engineering student, already had doubts that engineering was too much of a male-dominated business for her.
No doubt that No Doubt is back.
When Hales then edged Morkel wide of Morris's right hand at third slip, only to see the fielder pluck the ball from close to the turf after it appeared to have gone past him, both openers had gone without adding to their overnight scores: already the nagging doubts that can invade the minds of England supporters were there.
Already there is considerable doubt that Argentina will now agree to the kind of hemispheric free-trade agreement that Mr. Bush himself, with Mr. de la Rúa at his side, said last year was a major goal of his administration.
