What is the proper etiquette on telling someone that they crossed the line and that you don't want to be friends with th

[Madison 3:16 Anderson Rhodes]

There is this guy that I added to my Facebook literally over 3 years ago. In those 3 years, we have said maybe 8 words total. All through comments about a tv show...not even direct to each other...more of a talking out loud "I liked this or that about this show" months apart...

Not too long ago I posted a status that I had a bad day, that I'm tired and I can't wait to go to sleep. Nothing major, nothing to get attention, just burnt out from working so much and needed to vent a little (also letting my family know I'm going to sleep and don't bother me lol)...

Anyway, he commented. Which was nice of him. He seemed like a good hearted person who was on and happened to see it.

Then he messaged me and basically said EVERYTHING that I didn't need to hear. I don't know him, he doesn't know me AT ALL. He said, I'll never leave you and I love you. I got upset and straight up told him that I didn't like that, it's wrong to say, and it's wrong to promise people things when you can't predict the future.

THAT was the last thing I needed to hear (part of why I'm so depressed/going to therapy..losing someone).

Then AFTER I made my point VERY clear...he proceeded to end the convo with good night baby. I told him off and told him to give me space.

Today, he's back again after a few days of leaving me alone. Liking everything, commenting, and even messaged me...I ignored it all. I don't want him all over my f'n wall. I want to unfriend him and TELL him why & do it PROPERLY...how???
He knows about me losing someone so we can't say, "he didn't know and just happened to say the wrong things.." HE KNEW...