Let me tell you a little secret about me.
讓我告訴你個(gè)秘密。

通常在給別人意見(jiàn)時(shí)使用

Let me tell you a little secret about me. When I was a child, I wanted to be a movie star. I thought it was not easy, so I didn't try. But you need to know that nothing in life is easy.
給你講個(gè)事兒，我小時(shí)候想成為電影明星，我覺(jué)得這可能挺難的，所以就沒(méi)有去嘗試。但是你必須知道，生活中沒(méi)有易事。

Let me tell you a story
我給你講個(gè)故事

通常是給人講大道理

Let me tell you a story. One day I met a beautiful girl and she asked for my number. I didn't give it to her because I thought I was too poor to have a girlfriend.
我給你講個(gè)故事吧。有一天我遇見(jiàn)了一個(gè)漂亮的姑娘。她管我要電話號(hào)碼。我沒(méi)有給她。因?yàn)槲矣X(jué)得我太窮了以致于沒(méi)法找女朋友。

The next day I see her walking hand in hand with a bum. So sometimes you don't know what people value in you.
但第二天我就看見(jiàn)她跟一個(gè)流浪漢手牽手走在路上。所以呢，有時(shí)候你都不知道別人看重的是你的什么。

Life lesson
人生智慧

可以說(shuō)：Here's a life lesson.
Let me tell you a life lesson.
I wanna share a life lesson with you.

Here's a life lesson. Never get in a fight with a crazy person no matter how strong you think you are. Crazy always beats strong.
分享個(gè)人生智慧給你。永遠(yuǎn)不要跟瘋子打架，不管你覺(jué)得自己有多么強(qiáng)壯。因?yàn)榀偪裼肋h(yuǎn)比強(qiáng)壯厲害。

Share one's experience
分享經(jīng)驗(yàn)

Susan shared her experience of love with me over coffee. One thing she said was to never waste your time in a relationship if the way you see someone changes for the worse.
喝咖啡的時(shí)候Susan跟我分享了她的愛(ài)情經(jīng)驗(yàn)。如果你的他的看法變壞了，就不要再跟他浪費(fèi)時(shí)間。

Something you can't learn in school
有些事情是在學(xué)校里學(xué)不到的

How to run a company is something you can't learn in school. You have to actually try it to see how it's done.
如何經(jīng)營(yíng)一家公司是你在學(xué)校里學(xué)不到的。你必須親自嘗試，然后了解如何做到。