The Ruler Of Darkness - Chapter 24Book 6:

Life Mission – a game that has become reality.

“You’re not taking me to bed. Ever.”

It is eight or nine years for her to meet her first love again. In the gas station of highway, she sees him walking from the grocery store. She looks at him, not believing what she sees and asks, ‘Do you still remember me?’ He looks at her, with a bottle of mineral water in his hand, and says peacefully, ‘Yes, even if you became ashes.

- Description from Novelupdates

A con-man and policewoman that are legends of their respective professions suddenly die, then are reincarnated and return to the Tang Dynasty of ancient China as little kids.

Accepting their second chance and forced restart, they choose to use the modern knowledge and specific talents that they have in their previous lives in order to live comfortably in this new life.

- Description from Novelupdates