Taking advantage of my girl brother's stupidity, fooling her into being my wife

After Chen Kai was reborn, the system was bound. The first thing to do after rebirth is to trick your female brother Qin Xiaoyu into being his wife!
"Little fish, let's discuss something."
"Okay! Just don't borrow money."
"Be my wife."
"I treat you as a brother, and you want me to be your wife?"
"Don't get me wrong, I just hope to use my wife's relationship to maintain our brotherhood!"
Qin Xiaoyu nodded innocently, "It seems to make sense, but why do I feel that something is wrong?"