Hello plumbing reddit,  
I could really use some help with this situation I foolishly got myself into! So my wife and I renovated out bathroom within the past month, and got a beautiful new vanity for it.  
  
Unfortunately the new vanity hasn't been the best fit for the old vanity. The biggest issue; the hookup for the hot water to the faucet was causing a drawer to stick out. Now I'm a woodworker and could trim the drawer, but I hate doing that to a brand new, finished vanity. So opted for attempting to shorten the hot water hookup. My plan was to shorten it and slap a brand new sharkbite faucet hookup to it. The lot of the plumbing in the house is 1/2" copper pipe. At glance, this *looked* the same....

I went to cut it. It was extremely hard to cut, which should have been my clue to stop, but I kept going. But I cut it, cleaned it up, deburred. And, sharkbite wouldn't fit. Great. I learned fast, this pipe was NOT conventional copper pipe.

What it appears to be (and correct me if I am wrong), is chrome-plated brass pipe. Most sharkbites aren't compatible with this. The pipe, I'm not 100% sure, but it almost looks brazed on. My only option (as I had the entire water to the house shut over this...) was to put a high pressure hose and hose clamp it to a piece of copper pipe with the sharkbite faucet hookup. Today a week later, it popped off the copper and made a disaster of a mess. Fortunately I was home. I got it back on, doubled clamped really hard, scuffed the pipes for the hose to grip better.

I need a more permanent solution than the hose, but I'm not sure how to move forward here. What do any plumbing pros here suggested I do? From the photo, do you think I could unscrew this brass pipe from the wall? If I can't, how can I hook something new, safe, and secure to it? Are there compressions for this if sharkbites aren't an option? Would a sharkbite IPS fitting work on it?

I really have NO clue how to move forward with this, so I'd appreciate any advice. It looks brass to me, I don't know what to buy or what is compatible with this goofy pipe. The ID is 1/2. The OD with a digital caliper measures an odd 11/16. It's an older home from 1974. Thank you.

Help to come up with a permanent repair for this predicament