The child's smile never wavers though her eyes are knowing.

Her smile wavered as she looked into his eyes.

Her smile wavered a moment, then came back even stronger.

When his back was turned, her smile wavered and broke.

She shot him a warning glance but her smile didn't waver.

Her smile wavered at that, but she did not stop.

The smile wavered as she found Travis looking down at her strangely.

Her smile wavered, but at least she was smiling again.

For a moment, Mary's smile wavered and she bit her lip.

The girl's smile wavered for a moment, then returned, but was less strong.