You can believe that Jesus is the prophesied Messiah, the Saviour, and it is that belief that makes you a Christian.
Getting better but a Christian also believes the Messiah is God. A professed Christian who rejects what the Bible says in many places can't be a true Christian. Otherwise, there would be a contradiction of monumental proportions. Calling Jesus not God is tantamount to calling the Father not God. The simple Biblical fact of the matter is the Word was with God and the Word is God, and the Word became flesh and dwelt among us, and Christians beheld His glory, the glory as of the only Begotten Son of the Father, full of Grace and Truth. Hence, the two persons, Father and Son are God. To refute that would mean refuting the deity of Jesus.
