Rakuin no Monshou - Volume 4, Prologue

Her first encounter with Qin Sijue is an unexpected one. While trying to hide from her pursuers, she accidentally barges into his changing room. Yet, their paths crosses again fatefully—after a fake marriage, she legally becomes his bride. She imagines that they will only interact before the agreement ends, after which they would have nothing to do with each other. However, Qin Sijue comes over with two red booklets—their wedding certificate. “Take them for an appraisal and see if they’re real”.

Is it wrong to face the perils of Dungeon alone, in a single-member guild blessed by a failed goddess? Maybe.

Is it wrong to dream of playing hero to hapless maidens in Dungeon? Maybe not. After one misguided adventure, Bell quickly discovers that anything can happen in the labyrinth-even chance encounters with beautiful women.

Only problem? He’s the one who winds up the damsel in distress!

The system asked: “What happened to the slag man?”
Bei Yu Tang answered: “Destroyed.”
The system asked again: “What happened to the boss?”
Bei Yu Tang immediately ran away!
Whether abuse of slag male or white lotus, she, Bei Yu Tang is very skilled.
But regarding abusing the boss, forget it!
Big BOSS’s fighting power is too strong, for small shrimp like her, it is still the best policy.
She did not want to destroy the boss, but was destroyed by the boss.
BOSS lord: “Wife, who do you want to destroy, let your husband do it.”
Bei Yu Tang excitedly replied: “System monarch.”
System: (face filled with tears and dead … …)
[Story of pampering, 1v1, Straightforward story, Easy and humorous]

- Description from 69shu translation

This is a cliché story about two young people saving the world.