Repentance: Strong's Hebrews ( H7725:שׁוּב ) to turn back, return, a wholehearted turning to God.
(NOTE: The different way repent translates in Hebrew vs Greek. John wasn't speaking Greek, nor was he preaching to gentiles. Gentiles had no relationship, no covenant, no hope & were without God (Eph 2:12)
This is totally untrue! John spoke and wrote a very simple kind of Greek. John, and 1,2,3 John are the easiest books in the NT to translate. When I was studying for the final of 1st year Koine Greek, we had 7 passages we had to translate, and also write down all the verb forms used in the passage. When I read the passage from John, I never went back, it was so easy. Revelation is harder, but he still uses syntax and word order of Hebrew, in the Greek text. These became known as "Hebraisms" and John was the only user of this, because his Greek wasn't very advanced. The consistency in his writing helps us to know they were written by the same author.
Further, there are NO extant, early Hebrew manuscripts of any book in the NT. Koine Greek was the Lingua Franca of the Roman Empire. It was one of the conditions God set up before the birth of Christ, so the gospel would spread rapidly, along with Pax Romana and safe roads and seas. Because almost everyone understood Greek, the writers of the Books of the NT wrote in Greek, so the maximum number of people in the Roman Empire would be able to read or hear the originals and copies. Even Matthew, who wrote to Hebrews, and the writer of Hebrews, did not use Hebrew. Hebrew was a dead language by the 1st century AD. The boys learned to read Hebrew in Torah school, but not many spoke it. Besides, Aramaic was the language used in the ancient near east, never Hebrew, in that area. Most Hebrews had lost their Hebrew by 300 BC, when the OT was translated from Hebrew into Greek. it wasn't till the 8th to the 10th centuries that the Masoretes added the vowel pointings to help with pronunciation.
The Romans employed many people and when they built a new city in that area, they used Hebrew craftsmen, like Joseph the carpenter, father of Jesus. It is likely Jesus also used Greek when working, before he began his ministry, as when Jesus was interrogated by Pontius Pilate, there is no translator mentioned. They both spoke in Greek!
Actually there were many gentiles looking to know God. The Roman centurion, the woman at the well (Samaria), the people in the Decapolis were mostly Gentiles, and Jesus healed a demon possessed Gentile man, who became a follower, when he was on the east side of the Sea of Galilee. Also the woman who begged Jesus to heal her daughter was a Gentile, and when Jesus implied Gentiles were dogs, she replied the dogs eat the food which has fallen From the Master's plate to the ground.
Jesus came for the Jews, but so many rejected him, that he opened up the gospel for everyone, which was always his purpose.
I suggest you read the Bible more, maybe learn Hebrew and Greek, and study some history, before you going throwing out utterly wrong statements about the Bible. The NT was written in Greek. No Hebrew at all. You need to look in the OT for Hebrew!!