From the bottom of my heart

常用于第一人称，该短语意为你的态度非常真诚。

You're the best player on the basketball team. I mean that from the bottom of my heart.

你是篮球队里最优秀的选手。我这是肺腑之言。

I think you are a wonderful person. Really, I mean that from the bottom of my heart.

我觉得你非常优秀。真的，我说这话是发自肺腑的。

Get at the heart of the matter

讨论主要的问题和担忧的事。

I'd like to get at the heart of the matter by discussing our marketing proposals.

我打算把我们的销售建议作为主要问题来讨论。

She didn't waste any time and got right to the heart of the matter.

她不浪费一分一秒，直接进入主题。