Anik had that ethereal look, but no one doubted her strength of character or spirit.

Beware of one who would make you doubt your own strength.

"Certainly," he replied, miffed that I could doubt his strength.

There is no cause to doubt her strength.

"We must give them no reason to doubt our strength."

But no one who thought about the prospect could doubt his strength.

Always now he doubted his strength and dreaded the trial of his power.

She doubted her own strength to deny him.

Being hired was tough; employers often doubted her strength and ability.

How could she have been so foolish as to ever doubt his strength of character?