But you still start off in a state of non-belief. Here is a claim that is similar to God:
"There is an all loving God made of Pasta. His name is the flying spaghetti monster, and if you worship him you get to go to his beer and stripper factory in the sky."
Do you disbelieve it or believe it? Why?
There are a lot of logical reasons why philosophers have argued for the existence of God.
It is generally assumed that if God exists, He'd have certain characteristics consistent with the traits of someone who would create us; or that, if God exists, there would have been a motivation that He had in His creation of us that would involve reaching out to us.
There would also probably be a logic in all of this that would dictate certain ideals and beliefs for a God.
The idea of a 'flying spaghetti monster' is merely an attempt to make it all sound absurd -- the idea that there is a place full of beers and strippers solely for us is also absurd, as there is no moral quality here; no concept of right or wrong worked into this but merely a concept of pleasure.
If you were to listen to the description of Krsna in the Bhagavad-Gita he does not sound anything like a human in appearance... He might as well be a flying spaghetti monster.
However, in Christendom we believe that God created man in His Image, which also seems logical -- that the highest animal of His Creation would be special, and that He would be interested in modeling it after Himself if He loved the creature well.
There is a logic in this if you bother to try to understand our perspectives.
I've always liked this one better. It has the questions and a nice sunny background.
"but how can we believe it is the word of God?"
It is a book of high values that shows a clear prophetic chain from the beginning to the necessary conclusion -- there is an entire evolution that would make sense, as at certain points in history a certain message would be appropriate, and such a message was delivered unto the Israelites and then eventually unto the whole world through the messasge brought to Christ.
Of course, there are certainly other books that preach high morals that also have religious ramifications; however, most of these have no prophetic chain that goes with them that would be indicative at all of it coming from God Himself.
Other than Hinduism, there really is not a competing conception of Godhead and the prophetic succession for a religion that is coming to the people as the message of God is revealed...
Hinduism is a good thing -- a worthy thing to debate and discuss. The views of the Hare Krsna are compelling, however, they are also fraught with a lot of issues that go back to elitism...
And Hinduism in general can often be a petty religion based on caste which discriminates against people far and wide.