“Yes, I believe in God.”
Well, that's great. I believe in God too. But what does that mean? Who is God? The question is important. Here, when I say “God”, I mean the God who created the universe. The one God, who created heaven and earth.
So, if you believe in some other god such as Hanuman, Osiris or Amaterasu (the Japanese Sun goddess) or even Tsuki-Yomi (the Japanese Moon goddess) that would mean no, you don't believe in a singular God who created heaven and earth.
Do you believe in that God? The one Creator-god?