The Substitute Bride - Chapter 4

I was possessed by the game (forced).

Bai Aoxue, the best mercenary in the 21st century, is accidentally sent back to the Chengxi Dynasty in Great Continent due to an explosion in her mission, and trapped in the first daughter of Prime Minister. After her rebirth, she is set up by her father to marry the 5th prince Jun Yeyan who wears a mask all day long.
In the face of bloodthirsty enemies, discord between brothers, collusion among courtiers and invasion of enemy state, can Bai and Jun resolve the crises? What will happen to their political marriage? How will the fierce battle for the throne end?
With many twists and turns, the book brings you to experience palace revolution, love and hatred thousands of years ago.

- Description from Novelupdates

An 18-year-old girl who lost her family in an accident, Yamano Mitsuha falls off a cliff one day and transferred to a different world with a civilization level of medieval Europe. Mitsuha who discovered it was possible to go and return to Earth after a deadly fight with wolves decided to live in both worlds.

「For the sake of security in old age, I will aim for 80,000 gold coins!」

I will try not to let strange things circulate and distort the progress of the world, but I won’t hold back for the sake of my easy life and safety! While carrying three handguns along with words and deeds that appear decent, in her head, Yamano Mitsuha is a sly girl.

Making an effort to make money even with a small body that looks like a child to foreigners!

Oh, my secrets are too dangerous, you said? It’s fine, it’s fine! I’ll transfer away when push comes to shove!