Konoha's Tag-System Ninja - Chapter 11 - : Reporting!

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

Over a million years ago, the first human contracted with the first Spirit. Ever since then, Spirit use has become commonplace. Humans used Spirits to carry items and start fires. Eventually, even start wars. Thousands upon thousands of years past and one day, one human did the impossible. He transcended his mortality and ascended to the realm above.

Chen An traveled to the world of cultivating immortals, and his cultivation talent was extremely poor. He was stuck in the third level of Qi refining for many years and could not make further progress.

Seeing that there is no hope of cultivating immortality, he chooses to return to ordinary life, and marries a wife to enjoy the ordinary happiness.

As a result, on the night of their marriage, they returned to the fairyland overnight.

It turned out that marrying a wife and enjoying ordinary pleasures was his way to become a fairy, and it could directly save him thousands of years of detours.

- Description from novelbuddy

Chu Sihan, the county magistrate of Xuan Yue Country, is an exceptionally handsome prodigy who had risen to fame since he was a child. However, the National Preceptor prophesies that he would not live to the age of thirty, unless he marries the Lu Family’s daughter from Liu Yue Village.