It comes from within, that much I know, and few people are lucky enough to be blessed with it.

那是发自内心的，而我知道，只有少数幸运的人能得到这样的幸福。

youdao

I don't pretend (that) I know much about the subject, but...

我不敢说自己对这个主题有多了解，但是…

《牛津词典》

I hope you can recognize by my saying that how much you do know about the subject.

我希望你能从我的话中认识到你究竟对这个主题了解多少。

youdao

Look, Bella, I know I'm notthat much fun to be around, but I can change that.We can do more stuff together.

VOA: standard.other

I know that you are a judge down here and much respected. So, looks like you've beaten the rap."

我知道你在下面是个广受尊敬的法官,看来你混得很开啊"

耶鲁公开课 - 古希腊历史简介课程节选

I would guess that's pretty much, you know, apart from, you know, all the usual, well-known things.

我觉得这些差不多了，加上那些众所周知的地方的话。

鲜为人知的名胜 - SpeakingMax英语口语达人

But I don't have that much more information but what I do know is that there has been a lot of damage.

NPR: Hurricanes Wreak Havoc In Haiti And Cuba

Now that I know as much as my body knows, I make different choices.

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But I want to qualify that by saying, I don't know that much about the Tongass.

NPR: Rocky Mountain Activist Carole King