Keiko forced a weak grin, although she knew he couldn't see her face.

Then he suddenly took a deep breath and managed a weak grin.

He gave her a weak grin and shook his head.

"I thought we were here to talk about your qualities, not mine," he said with a weak grin.

Tom tried to smile, to look happy, and finally managed a weak grin.

He looked at her, giving his friend a weak grin.

For some reason that brought a weak grin to his parchment-pale face.

I gave a weak grin, trying to play the part of someone who'd lost his job.

Casey gave him a weak grin, and he turned away.

He gave them a weak grin and began walking again.