"Love our enemies" is something Jesus showed us in practice.
Loving involves, of course, telling them the truth. "Admonishing the sinner" is Mercy, too.
Thank you. It's not an answer I enjoy, but that is the point of the Bible. If God wanted us to do whatever we wanted, there would be no need for scripture, since following our own whims is what we do naturally. He wants us to follow His guidance, whether or not it matches the choices we would make on our own. I don't always succeed, but I do my best to let Him guide my life.