Maybe someday you will see reality but I sincerely doubt it.

I sincerely doubt if both proposals will ever be accepted.

I sincerely doubt if you would have given us your ship.

And after this, I sincerely doubted if he'd want to date me, either.

I sincerely doubt most parents of boys actually give them this wide range.

I sincerely doubt he could get many heads of state here for a conference such as you suggest.

In fact he quite sincerely doubted whether anyone would even try.

"I sincerely doubt we'll need all four between now and then."

But I sincerely doubt you have anything to worry about for the present.

I sincerely doubt if there is more than one place where these crystals grow.