We only need to believe that Jeus is God (John 8:24) If you say that we need to beleive that Jesus is 2nd then you are adding to scripture!
Rather you have isolated one verse of Scripture and have based your theology on it which has resulted in a warped view of soteriology.
What else did Jesus say? What else does the Bible say about salvation?
In 1Cor.15:1-4, Paul said, "I declare unto you the gospel...by the which you are saved."
How can you ignore such a straight forward statement--that you need the gospel to be saved, not simply to believe that Christ is God.
Romans 5:1 Therefore being justified by faith, we have peace with God through our Lord Jesus Christ:
--We are justified by faith. Another important part of salvation.
Ephesians 2:8-9 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast.
--One of the clearest passages on salvation there is:
We are saved by grace (the grace of God) through faith. Through faith in what? Through faith in the shed blood of Jesus Christ, in his atoning work on the cross. It is not of works. It is entirely by faith. It is by the grace provided by Christ, a gift that we don't deserve, but Christ provided it anyway even though we are wicked sinners undeserving of this precious gift of eternal life. There is more to it than just believing that Christ is God.
Jesus said to Nicodemus: "Except a man be born again, he cannot see the kingdom of God. Nicodemus was not born of God. I think that Nicodemus believed that Christ was the Messiah, (God), but that didn't make him saved. He had to be born again. But what did that mean. Jesus launches into a discourse of what it means to be born again. Do you know what it means to be born again? If you do not perhaps you are not saved. It is the only way to heaven. One must be born again or there is no way to heaven. It is not simply believing that Jesus is God.
Much more is needed than simply believing that Christ is God.
To hang all your theology on just one verse of Scripture results in a warped view of God and Christ.