When I went to the Youth Evangelism Conference in Oklahoma City this year, the preacher who gave the massage described “belief” kind of like this:
God's Word says that all who believe in Him shall have everlasting life, right?
John 3:16 - For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life.
Well, if the literal meaning of this true, then all people--humans, angels and demons alike--who believe in God's existence will be saved. In this instance, even Satan himself would be saved, because he believes that Jesus died on the cross to save people from their sins, even though he despises it. However, we all know that Satan will NOT be saved in the end. He's going to be cast into the fire.
Revelation 20:10 - And the devil who had deceived them was thrown into the lake of fire and sulfur where the beast and the false prophet were, and they will be tormented day and night forever and ever.
This must mean, then, that there is a deeper meaning of belief. Not only to believe that He exists and what he did for us, but also to acknowledge Him with love and respect, and to have faith that His Word is pure, holy and true.
I guess, then, there are two kinds of belief. One is a belief that something exists, and the other is a faith that that entity will do (and have actually done) what they proclaim.