Tied to Destiny (Bonten Ff)

Zharia was just an ordinary college student looking for a way to kill time. But curiosity becomes a dangerous thing when she stumbles upon a cryptic, dusty volume in the corner of a forgotten antique store. Drawn to its pages, she buys it without hesitation-completely unaware that she has just purchased her own undoing.
Inside the book lies a brutal world ruled by a ruthless syndicate known as Bonten. As Zharia reads, she watches a tragic female lead suffer unimaginable horrors at their hands. Out of pure sympathy, Zharia makes a careless promise to the pages: "If I could cross into your world, I would do everything to save you."
She thought it was a joke. Destiny did not.
A sudden, fatal slip in her own bathroom cuts Zharia's life short-only for her to wake up trapped inside the very pages she just closed. There is no escape, no logic, and no way out.
Now, staring directly into the eyes of the fragile woman she swore to protect, Zharia realizes the terrifying truth of her new reality. The monsters from her book are real, they are watching, and they are coming.
"What the heck... that was supposed to be a joke!"
Can an ordinary student outsmart the deadliest yakuza in Tokyo, or will she become Bonten's next victim