Real, biblical repentance is changing our mind by turning from unbelief to believing on the risen Lord Jesus Christ.

"Repent of sins" is unbiblical as shown by the two KJB verses below.

Now after that John was put in prison, Jesus came into Galilee, preaching the gospel of the kingdom of God, and saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel.
Mark 1:14 - 15 KJB

And God saw their works, that they turned from their evil way; and God repented of the evil, that he had said that he would do unto them; and he did it not.
Jonah 3:10 KJB

God repented. Did He sin? No. So does repent mean turn from sin? No, because God repented because He was going to overthow Nineveh by doing evil to them but then he did not do the evil to Nineveh. The way God went from saying He would do evil to Ninevah, to not doing the evil to Ninevah's people, is that God changed His mind on what He was planning to do/going to do.
Repent means a change his mind.

@RepentanceExamined