Tensei Shitara Slime Datta Ken (WN) - Chapter 258

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

Ye Family goes bankrupt, and her fiancé's family watches coldly.Ye Li signs a contract and marries her fiancé's uncle in a flash marriage.After marriage, Ye Li is determined to repay the debt of one hundred million with interest, hoping to give Fu Yanci freedom so he can be with his true love.When it reaches 5 million, Fu Yanci gets upset.At 50 million, Fu Yanci leaves home for three days.When finally paying off the full one hundred million, Ye Li is cornered by the man: 'Divorce, huh? Sure!!! The family property is yours, and so am I! I'll follow you everywhere!'Ye Li: ......

Ever since she transmigrated, she was blessed with an inbuilt anti-poison detector.

Living carefree at home is the greatest shortcut—- My house is the world’s greatest magic power spot, that being the case both my house and I were summoned to another world by some guys who were aiming for it. However, I’ve been living in this place for many years and my body is, apparently, abnormally overflowing with magic. Due to some unforeseen circumstances by those guys who summoned me, they quickly ran away. Be that as it may, there are some ill-mannered people who covet the magic leaking out of my house. I won’t give up my house to those people! I’m going to wield my power as I please!