How To Avoid The Imprisonment Ending

One day, I opened my eyes and found myself inside a character development simulation game.
The character I became? A caretaker responsible for raising Mabel, the protagonist of the game!
[If you reach the Happy Ending, you can obtain clues about how to return to your original world.]
With the system saying that, I threw myself into the mission, determined to reach the ending and make it back home.
First of all, no matter the world, you need two things: money and power!
So I joined the knights’ order to earn some income, when out of nowhere, the young duke came looking for a fake lover or something?
“Become my fake lover. I’ll compensate you generously.”
“But still…”
“Ten times your current salary. That’s what you’ll earn while pretending to be my lover. On top of that, I’ll provide a dowry large enough to cover any damage to your reputation when we break up. That should be enough, right?”
“I look forward to working with you.”
The money was too good to pass up, so I entered a contract relationship with the young duke.
I did my job well, got paid generously, and everything was going smoothly.
“I like you, Sonnet.”
Until he actually fell in love with me.
[Obsession level has been unlocked.]
[If the obsession level exceeds a certain threshold, the probability of reaching the Imprisonment Ending increases significantly.]
“…An Imprisonment Ending?”
…Looks like the road home is going to be more dangerous than I thought.