Prophecy always points to Jesus:
Revelation 20:10 Worship only God. For the essence of prophecy is to give a clear witness for Jesus.
True prophecy doesn’t draw attention to the prophet, but to God. This means it must be spoken in love, which has lasting value. This doesn’t mean it’s always pleasant for people who aren’t listening to God, as Jeremiah and other Old Testament prophets demonstrated. Even so, a hard message can be valued and save people from their sins. Jonah (who prophesied to Nineveh, which then repented and was saved), and Nathan (who challenged King David about his sin with Bathsheba) are two good examples of this.
The focus is always on God and His son, Jesus.
At a practical level, true prophecy actually happens:
Deuteronomy 18:21-22 But you may wonder, ‘How will we know whether or not a prophecy is from the Lord?’ If the prophet speaks in the Lord’s name but his prediction does not happen or come true, you will know that the Lord did not give that message. That prophet has spoken without my authority and need not be feared.