I can give you my perspective on why I believe there is a God and also that Jesus is His Son.
To start off, I believe that something created this Universe. I simply cannot accept that fact that it "just happened". Now, even though this goes to the point of proving, at least to me anyway, there is a god, the question now becomes who is god. Throughout history there have been many representations of god and who He is. So, one must ask themselves how do I know which god is the "correct" or "real" god. Because we live in the 21st century, we have the advantage of hindsight to history. We can see the effect of mans choice on who god is. If you look at Islamic countries for example. Why are they so afraid of Christianity? Why is it that Christian countries allow Muslims to worship but it is not reciprocated in Islamic countries? My mother used to tell me, the truth is never afraid of a lie but a lie is always afraid of the truth. Also, how many times in history has an Islamic country helped a Christian nation? I don't believe the Lord would allow a country that worships a false god to be needed by a country following Him.
Another point I want to make is this. Sometimes I imagine myself as God and ask myself, "What would I do if a man on Earth claimed to be my son, and wasn't?". Would I sit by and allow this man to change history in my name? The answer I come up with is a resounding NO! If I were God, the name of Jesus would of been wiped from history the second He took His last breath. No one would know who this blasphemer was. When you look at history and see the effect Christ has had on it, there is no question God is not silencing the effect Jesus is having on the world.
Another point is this. Prophecy. The most important one to me is Israel and how she is looked over. When you look at Israel consider two things. She is the only nation in the history of the world to have
disappeared and then returned. Also, when you look at her enemies, she is surrounded by them. Her enemies are countless. But, yet no nation has been able to touch her. Something peculiar is
going on here. The Bible speaks about God's love for Israel. Is this just happenstance? I don't think so.
There are other reasons I believe but they are mostly personal. When I gather the evidence together I have come to the conclusion Jesus Christ is the Son of God. I also think God Himself presents
Himself to those He knows will accept Him. I think He sees me as one of those and has taken supernatural steps to make me believe.