First, nslookup is a horrible tool to query DNS servers. If you want to know what is actually going on, you have to use dig.
2nd, you can't control what name your nameserver gives for your computer from your computer. The nameserver needs to know your name to reply with it. You would need to create a forward and reverse lookup for quartslove, and most home routers don't allow you to do that. You would have to be running a proper nameserver, not just the caching server build into home networking devices.
3rd, why? The only people who can find your computer on the private 192.168.50.0 subnet are those on your LAN. Just give yourself a static mapped IP address, and let them connect to you that way.