The mother was growing less certain that her daughter would actually take her own life.

Minerva grew more certain of that with every passing instant.

She grew ever more certain that she was his primary occupation.

And death grew more certain with every passing moment.

Trevize had grown quite certain he knew what was going on.

Sparhawk moved towards them, growing more certain as he did so.

In fact, she was beginning to grow certain she would never see him again.

He grew both more anxious and more certain of finding her.

Enough time passed that Anna grew certain there would be no answer.

Now as the picture grew even less certain in his mind, the doubt vanished.