Ivan was suddenly unsure of where to put his feet, or his hands.

She realized that he hadn't introduced himself and was suddenly unsure.

Jerusha hesitated, suddenly unsure of what she was about to do.

He came to the corner he was expecting and then stopped, suddenly unsure.

I felt suddenly unsure and alone, hesitating on the brink of the gap between us.

Finding himself suddenly unsure, the Doctor reached tentatively for her hand.

He nodded, suddenly unsure of what to do with his own hands.

She paused, suddenly unsure of where to go, which avenue to take.

He asked for a minute to digest what she had told him, which had made her suddenly unsure of herself.

Ross hesitated, suddenly unsure of what he should say.