The sumptuousness of the hotel's decor is truly unmatched.

sumptuousness 是形容词 sumptuous 的名词形式，sumptuous 意思是"豪华的、奢侈的"，后缀 -ness 表示"性质、状态"。 sumptuousness 指"豪华、奢华的状态或品质"，用来形容极其精致、昂贵或富丽堂皇的事物。