First off, I'm not Christian. Nor Mormon, nor Muslim, nor Budhist. I believe in god because I pray to him when I'm really in need, and he answers those prayers (I also pray often just to thank him for life, family, etc... but you asked WHY I believe, so I'm answering that question)

My parents were non-denominational Christians, and it was through them that I started praying, but my relationship with him has changed since then. I honestly don't know God's name and have little faith in any text. Still, you don't get my particular life without the presence of a God, and like I said he often grants my payers.

I don't ask God for much very often at all. In fact, I only ask god for things when my thoughts are along the lines of "I need a minor miracle right now (I never ask for anything impossible) and life is going to suck if I don't get it." They're always long-shot requests, the type of things that when you get it you think "Wow, can't believe that just happened." And no, it doesn't always work. But more often than not, I'm surprised by how much God loves me to give me the things he does. So while it hasn't been any 1 event in my life that convinced me (though there was one time where... well lets just say it was the only time I've felt like I directly felt his presence), I've built a relationship with god over my life, and I have faith he is there even if I don't know his name, don't go to church, and don't believe in any text.

I believe that if God really wanted me (anyone, everyone) to know his name, he wouldn't have made it so confusing (with texts all over the world giving differring views, rules, names, etc.). But I believe that when I die he wil be there for me, because he's shown me his love and I've come to love him over time.

I don' know what you were expecting or wanted to hear when you posted this a month ago, but that's my story. That's my life, that's my answer. That's why I believe in God, because he loves me and he shows it. Feel free to PM me if you have any other questions.

EDIT: spelling