Both Uses

tremulous
in
The Handmaid's Tale
(Auto-generated)

She could smile and cry at the same time, one tear or two sliding gracefully down her cheek, as if on cue, as her voice lifted through its highest notes, tremulous, effortless.†
Chpt 3 *

tremulous = quivering (shaky)
Again the tremulous smile, of a beggar, the weakeyed blinking, the gaze upwards, through the round steel-rimmed glasses, towards the back of the classroom, as if the green-painted plaster ceiling were opening and God on a cloud of Pink Pearl face powder were coming down through the wires and sprinkler plumbing.†
Chpt 8

Definitions:

(1) (tremulous)
quivering (unsteady or shaky) -- usually from weakness or fear -- especially of the voice
(2) (meaning too rare to warrant focus)