看什么语境吧,如果是工作上比较正式的,就是 Please keep it confidential.
如果是朋友间的承诺,可以是:this is a secret between us,或者是更简单的:please don't tell anyone.
最好不用must,显得很生硬没礼貌.如果用Could you keep it as a secret?的问句,更容易被人接受 :)
看什么语境吧,如果是工作上比较正式的,就是 Please keep it confidential.
如果是朋友间的承诺,可以是:this is a secret between us,或者是更简单的:please don't tell anyone.
最好不用must,显得很生硬没礼貌.如果用Could you keep it as a secret?的问句,更容易被人接受 :)