2 Verbs to Use for the Word tremulousness

" Miss Van Rolsen did so in a voice she strove to make patient although she could not disguise its tremulousness, or the feverish anxiety that consumed her.

"About what, then?" I persist, in a voice through whose counterfeit playfulness I myself too plainly hear the unconquerable tremulousness; "may not I hear?or is it a secret?" He does not answer; it seems to me that he is considering what response to make.

2 Verbs to Use for the Word  tremulousness