He sounded so sincere that I had to smile again.

He sounded sincere, but did she just want to believe him?

"It's too bad," Will said, trying to sound sincere when things were playing right into his hands.

"Of course," he said a beat too late for it to sound sincere.

He sounded sincere, and it seemed the only means of leaving the room.

I tried to sound sincere, but it was an effort holding a conversation.

If this kid was telling the truth, I didn't think he'd sound nearly so sincere.

Richard didn't have to try to sound sincere, because he truly was.

Why was she so bad at trying to sound sincere?

It sounded sincere enough, however, despite all he had done.