牛津电影里 65%
在内心深处;在心底
if you know sth deep down, you know your true feelings about sth, although you may not admit them to yourself
Deep down, you know I'm right.
牛津电影里 35%
本质上;实际上;事实上
if sth is true deep down, it is really like that, although it may not be obvious to people
Deep down, he's all fluff.
释义来自《牛津高阶英汉双解词典》第 9 版