He goes to the interview, uncertain of the job's nature.

For the first time in her life she was feeling uncertain of herself.

They were uncertain of him and would not be quick to want to take a stand.

She was uncertain of his age; not much older than herself, perhaps?

Now that the question had been put to him, he was uncertain of his answer.

Though she'd been sure this moment would eventually come, she was still uncertain of her answer.

He had never been so uncertain of himself in his life.

Now he is uncertain of his power over Jack and the others.

Then she pulled away from him, looking into his eyes as if uncertain of something.

The first time, the mother says, her daughter's doctors were uncertain of the cause.