doubt about/as to

It's still a little too cold for them to go out into the open, but as soon as the weather warms up, I have no doubt that the little one will be out and about exploring and playing every day.

The markets' view, as far as anyone can tell, is that the EU bail-out funds must be expanded to remove any doubt about their capacity to save Portugal and Spain.

Questions too, are increasingly being asked about the ability of science and technology to address the world's problems, as optimism about the future slides into doubt.