①くだけた不同意
Are you serious?
You must be joking 
Don’t give me that 
→You must be joking.There is no way you are going to business trip during the Coronavirus outbreak.


②配慮がある不同意
I’m sorry but 
I hate to disagree but 
→I hate to disagree but this product is completely out of date.


③保留する
I’m not sure about that 
It’s hard to say 
I wouldn’t like to say 
→I wouldn’t like to say, I mean, we don’t know anything to happen in the future.


④興味を示す
Oh did you?/have you?/were you?