With hasty indignation, therefore, and a tremulous voice, she said to him, "You do not seem afraid of not keeping your countenance when I come in with a basket of provisions—though one might have supposed—but it is only as Agatha that I was to be so overpowering!"
There are no more uses of "tremulous" in the book.
Show samples from other sources
She spoke timidly in a tremulous voice.
She tried to sound confident, but her voice was tremulous.