True God is a simple descriptive name of God. God is certainly the only genuine God but the name means more than that. In Hebrew, truth is related to faithfulness, so this name of God points to His reliability. God is true to His covenant with His people. The names Faithful God and God of faithfulness express the same idea.
True God in Hebrew:
’Elohei/’Elohim ’emet
Strong’s Concordance numbers: 430, 571
Bible references: 2 Chron. 15:3; Jer. 10:10
But the Lord is the true God, he is the living God, and an everlasting king: at his wrath the earth shall tremble, and the nations shall not be able to abide his indignation. (Jeremiah 10:10 KJV)
’Elohei ’amen
Strong’s Concordance numbers: 430, 543
Bible reference: Isa. 65:16 (NIV only, other versions have God of truth)
True God in Greek:
Ho alēthinos Theos
Strong’s Concordance numbers: 228, 2316
Bible reference: 1 John 5:20
We know also that the Son of God has come and has given us understanding, so that we may know him who is true. And we are in him who is true by being in his Son Jesus Christ. He is the true God and eternal life. (1 John 5:20 NIV)
The Only True God in Greek:
Jesus (Yeshua‘) used a slightly longer form of the same name:
Ho monos alēthinos Theos
Strong’s Concordance numbers: 3441, 228, 2316
Bible reference: John 17:3
And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent. (John 17:3 KJV)
Similar names for God are God of truth and the “Living and true God.” Jesus spoke of Himself as the True Vine and Faithful and True.