I do believe in monotheism which is believe in ONE GOD. Let me explain you that I am very supportive Trinity which shows the word "GOD" translates in hebrew language is ELOHIM. The definite of Elohim is more than one persons. Look at Genesis 1:26a, "And God, "Let us make man in our image, after our likeness..." Look at "us" and "our" which is a plural --- more than one single. Who God speaks to? God the Father, God the Son Jesus, and God the Holy Spirit are ONE GOD. 3 person in 1 GOD. Trinity = Tri (3) + unity in one GOD
"Hear, O Israel: The LORD our God is one Lord." Deut. 6:4
"Come ye near unto me, hear ye this; I have not spoken in secret from the beginning; from the time that it was, there am I: and now the Lord GOD (Father), and his Spirit (Holy Spirit), hath sent me. Thus saith the LORD, thy Redeemer (Jesus), the Holy One of Israel; I am the LORD thy God which teacheth thee to profit, which leadeth thee by the way that thou shouldest go." Isaiah 49:16-17
"For there are three that bear record in heaven, the Father, the Word (Jesus), and the Holy Ghost: and these three are one." 1 John 5:7