The word "most quavering" implies a shaky or trembling quality. Some possible antonyms for "most quavering" might include "steady," "strong," "confident," "firm," or "resolute." These words suggest a sense of stability or control, rather than wavering or hesitation. Other possible antonyms could include "smooth," "calm," "composed," "assured," or "certain." These words suggest a sense of ease or peace, rather than nervousness or uncertainty. Whatever the chosen antonyms, they should be chosen based on the particular context and intended meaning of the original phrase.