A young friend of mine years ago told me to, “Just tell them. They may not like it at the moment, but they’ll hear you.”
One perspective that I hold is that people do hear others even though it may take time for the comment to sink in. One telling is usually enough, too. It certainly goes both ways – if it’s a rich relationship.
Sometimes people need years to “hear it”, but it will happen. That’s the art of good communication.