Ok, so you're leaving it implicit (which means you're not answering the question). I already said that!
Do you realize that you're actually agreeing with me? And you've contradicted yourself here - you stated earlier that you're atheist, because you do not believe there's a god. Knowing and believing are not the same thing - you don't need to know something exists in order to believe it does, Belief is trusting that something exists without knowing.
But like I already said, it's cool if you want to leave it implicit. But then you haven't answered the question and it's quite likely the person who asked about your belief will be frustrated and probably ask you again later.
Another way to look at it
"Do you believe God exists?"
"We can't possibly know about that."
"I know, but what are your own personal feelings on the subject?"
Do you see that answering "we can't know" fails to address your own belief?
All I've been trying to say all this time is that your answer is correct but incomplete.