The Marquis Mansion's Elite Class - Chapter 9

A good-for-nothing man married a beautiful girl but was kicked off the bed on the wedding night. Furiously, he wrote a bill of divorce and ran away.
He was schemed a car accident in which he nearly lost his life. However, it turned out to be a blessing. He swallowed the soul that passed through the outer world, thus obtained superb medical skills and martial arts.
Later on, with the silver needles and invincible martial arts, he embarked on the road of counterattacks and was committed to his great dreams.

- Description from Novelupdates

Mu Jingzhe transmigrates into a book filled with sweet, doting love to become the useless supporting character who serves as a foil to the female lead. She also becomes the stepmom of five kids to her recently deceased husband.

In her previous life, An Xiulan had been oppressed and tortured by the members of Duke An's household. Her legitimate status wasn't enough to save her from the schemes of jealous siblings. For sixteen years, she tolerated the oppression inflicted on her but in the seventeenth year, she was pushed to death into the frozen lake.

Now she has reincarnated into the body of a youthful girl in the modern world who died in a car accident. She was given everything she was devoid of in her last life– family, love and education.

Graced with a new life, An Xiulan is determined to strive towards a better life. She will be the best daughter. She will study hard. And she will stay away from puppy love.

Nothing must come between her path to become a top scholar!

But there seems to be a hitch in the plan.

Why was the backbencher Han Zixin following her to the library, laboratory, playground and even the principal's office?

Wasn't Big Boss Han allergic to studies?

Why was he following the campus Belle?

…

Teacher: An Xiulan is a top student. We must preserve her at all costs.

Class Ten gulped as they recalled how a certain bro-con had supplied cheating slips to his model student sister in monthly tests subsequently resulting in her topping the exams!

Lu Xuan: No one is allowed to bully my sister!! Only I can bully her!

Everyone in class Ten: ????

A few days later, class Ten witnessed the delicate looking youthful girl chasing her self proclaimed brother with a hockey stick!

The delicate looking campus Belle wasn't delicate at all!

...

A delicate girl can't possibly make two big gangsters of Jingyuan Highschool dance on her tunes?