Naaman Changed His Mind

But Naaman became angry and stalked away. "I thought he would certainly come out to meet me!" he said. "I expected him to wave his hand over the leprosy and call on the name of the Lord his God and heal me! Aren't the rivers of Damascus, the Abana and the Pharpar, better than any of the rivers of Israel? Why shouldn't I wash in them and be healed?" So Naaman turned and went away in a rage.
But his officers tried to reason with him and said, "Sir, if the prophet had told you to do something very difficult, wouldn't you have done it? So you should certainly obey him when he says simply, 'Go and wash and be cured!'" So Naaman went down to the Jordan River and dipped himself seven times, as the man of God had instructed him. And his skin became as healthy as the skin of a young child, and he was healed!
Then Naaman and his entire party went back to find the man of God. They stood before him, and Naaman said, "Now I know that there is no God in all the world except in Israel. So please accept a gift from your servant." (2 Kings 5:11-15 NLT)

The Greek words for repent in New Testament are μετανοέω and μεταμεληθεὶς which mean "I change my mind". The Hebrew word for repent is שׁוּב, which mean "to turn back, return".

Like so many people in the world, general Naaman did not know the true God. He thought that all gods were the same, whether Aramean or Israelite. But after dipping in Jordan, he changed his mind.