From her QNA

How is he stuck in his world?

*she

https://imgflip.com/i/a18czn

Doesn’t really answer on why she can’t LEAVE.

Wdym, she can't travel to other Dark Worlds aside from Castle Town

Then why did you say that she’s in the confines of her world?

Because she doesn't LIVE in castle town, she just lurks around there sometimes, but also she's a DARKNER

It was confusing because I thought she was stuck in her world.

Well she is, but she wants to explore the rest of the game and follow the Fun Gang through the Dark Worlds but she'll turn to stone so she just stays in hers

Maybe she’s the only free one, and instead we’re all confined…

Well yes, she can see outside the game and she says she's "confined" because she can't explore the rest of the game, so she can't follow the Fun Gang without risking turning into stone