Both questions have the same answer, assuming it is true, and that answer is:
Yes! And now let me tell you what I mean by 'God' and 'believe'...
The wrong way to answer this question is:
Well, that all depends on what you mean by 'God' and 'believe'; because you may not mean the same thing as I do by these terms; and in fact there is great variation in usage; and indeed the very possibility of meaning for such terms depends on the conceptual scheme within which these terms are being deployed; and...
The right way is called witnessing to one's faith. Nowadays this requires courage - in public discourse especially.
Yes, you will necessarily be misunderstood, since an atheist cannot understand God and Believe in the same way as a Christian; since Christian understandings are ruled-out in advance by assumption.
But that is what is required of a Christian: affirmation of faith.
To answer the other way is an evasion. A deniable-evasion, true - but an evasion nonetheless.
Such a person is either too afraid, or too ashamed, publicly to identify himself as a Christian; and while this cowardice may be understandable given the negative sanctions, it is a sin - and the fact needs acknowledging and repenting.