She appeared on stage resplendently in a golden gown.

resplendently 是形容词 resplendent 的副词形式。resplendent 来自拉丁语 resplendere（闪耀），由 re-（加强语气）和 splendere（闪耀）组成，意思是"辉煌的、光彩夺目的"。resplendently 表示"光彩夺目地、辉煌地"。