Perhaps someone raised a Christian might 'believe' that, because familiarity breeds laziness, sadly. Converts, on the other hand, are a different matter entirely. Almost all the greatest saints were converts, either from atheism/paganism, or converting back to true Christianity after having fallen away. Converts have been the life blood of all sensible religion.

Don't group all Christians into one big barrel of stupidity.
Anyone with a sense of conscience will ask you for evidence, I'm sorry. We ask for the evidence of the Bible's authenticity, historicity, and place in time. Perhaps it might interest you to know that we have a larger number of copies of the Bible from a very early time; earlier, in fact, than we have copies of Tacitus, Pliny, or Cato. Who is to say that the events related in the much earlier Bible are any less real than those three eminent Romans? Everyone accepts that Tacitus existed, but we have evidence for his existence later than we have written evidence for Jesus' existence.
Anyway, your post jumps straight to Christianity. The O.P. asks about God, not Christ. Belief in God can come a thousand years before belief in Jesus.

I hope I haven't angered the fundies and evangelicals, but real belief and subjection to God comes by stages. You don't just up and believe in Jesus one day. Rational belief in the Father comes first, at least if you ever intend to keep the faith.