How do you unlock Fine Line Furnishings in stick RPG?

You can't unlock Fine Line Furnishings in Stick RPG. It is a pre-existing shop in the game that is always available to you.

However, you might be mistaking it for a different shop, or have encountered a bug. If you're having trouble finding Fine Line Furnishings, it's located in the bottom-left corner of the city map.

If you're still having trouble, please clarify your issue, and I'll be happy to help.