in your heart 在内心深处；内心强烈地感觉到；在你心中

【例句】
There's a place in your heart, And I know that it is love.
在你心中有一片净土，我知道那里充满了爱。

She knew in her heart of hearts that she was making the wrong decision.
她心底里明白她在作出错误的决定。