First you need to know what it means to believe. It is to accept that (something) is true, especially without proof.
Is there any proof that God exists? He may have revealed himself so to you but many still have questions concerning His Deity. To some nothing is convincing out there.
However the majority of us who believe we do so not because there is convincing proof but because we accepted and considered the bible a truthful story of the divine. We chose rather to be entirely positive, and to give credit that it’s true and an honest story concerning him. As for me I also had to accept that the Bible is true and somehow I’m convinced or trust that it is.
I mentioned ‘trust’ above. You place your confidence in God only when you believe first – believing his divinity, supernatural power, supreme being, sacred and holy.
Faith is what’s required of you to be a Christian, not evidence. “Jesus saith unto him, Thomas, because thou hast seen me, thou hast believed: blessed are they that have not seen, and yet have believed.” John 20:29
Hebrews 11:1-3,6-7 says, “Now faith is the substance of things hoped for, the evidence of things not seen.  For by it the elders obtained a good report.  Through faith we understand that the worlds were framed by the word of God, so that things which are seen were not made of things which do appear.  But without faith it is impossible to please him : for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.  By faith Noah, being warned of God of things not seen as yet, moved with fear, prepared an ark to the saving of his house; by the which he condemned the world, and became heir of the righteousness which is by faith.”
Substance, as in relation to the real fact of believing what is written concerning God, and that most important part you need is conviction.
Through faith we come to understand; understanding that even the worlds were framed by the word of God. I like the part where scripture says, “…for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him.”
But is there no evidence? You see it everywhere but God isn’t known by wisdom. “For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe.” 1 Corinthians 1:21
But blessed are you when he, “Whom having not seen, ye love; in whom, though now ye see him not, yet believing, ye rejoice with joy unspeakable and full of glory…Who by him do believe in God, that raised him up from the dead, and gave him glory; that your faith and hope might be in God.” 1 Peter 1:8, 21