As a matter of fact, ...
Who won the golf tournament? (那场高尔夫球比赛谁赢了?)
Well, as a matter of fact, I did. (其实，是我赢了。)
To be honest, ...
To be frank, ...
Frankly speaking, ...
Truthfully, ... (老实说……)
In all actuality, ... (实际上，……) *正式的说法。
Don't tell anyone.
Don't tell anyone. (别告诉任何人。)
I won't. (我不会的。)
Keep it under your hat. *一种惯用说法。
I have a confession. *confession “坦白”、“告白”、“供认”。
I have something to confess.
I need to tell you something. (我有事必须告诉你。)
I have a confession to make.
I have a secret.
I'm keeping a secret.
I'll fill you in. *fill...in“填满……”、“把……装满”。
So, what happened to my father? (那，我父亲出了什么事情?)
I'll fill you in. (我把一切告诉你。)
I'll tell you all about it.
I'll explain everything.
I'll tell you all the details.
I'll level with you. *level 表示“把……弄平”，但在这儿表示“说话不拐弯，直说”。
Quit lying to me! (不要对我说谎话。)
All right. I'll level with you. (好吧，我就直说吧。)
I'll tell you frankly.
I'll be frank with you.
I'll be open and sincere with you.
I'll tell you the truth. (我告诉你真相。)
That is about all I know.
What else do you know? (其他你还知道些什么?)
That is about all I know. (我知道的大概就是这些。)
I don't know anything else about it.
That's all I know.
This is just between you and me. *比较轻松的说法。直译为“你我俩人之间的事”。
This is just between you and me. (我们关起门来在这儿说。/咱们俩私下里说。)
What is it? (什么事呀?)
Let's keep our talk between us.
Let's keep this our little secret.
It's a secret.
Let me tell you a secret.
He can't keep a secret.
You've got a big mouth!
I don't have the guts to say that to my boss. *guts表示“勇气”。
A little bird told me. *说不清楚是从哪儿听来的，或者不愿意说出是从谁那儿听来的情况下使用。
A little bird told me that today is your birthday. (听说今天是你的生日。)
Wait. Who told you? (喂!谁告诉你的?)
I heard it through the grapevine. *grapevine 原意为“葡萄藤，葡萄属植物”，这里表示“谣言，传闻”。比较常用。
I just overheard it.
I didn't say anything. *表示自己没有泄密的说法。
I kept my mouth shut.
I didn't let the cat out of the bag. *表示“没有泄露秘密”的固定说法。
It was a slip of the tongue.
It was a slip of the tongue. (无意中说漏了嘴。)
Really? Didn't she know about it? (真的吗?难道她不知道?)
I spilled the beans. (我泄露了秘密。)
I stuck my foot in my mouth. (我把不好/失礼的事说出去了。)
I won't say a word. *用来表示“保证对谁都不说出去”。
Mum's the word. (我什么都不说。)
I won't say anything. (我什么都不说。)
My lips are sealed. (我的嘴很紧。)