Taking my sister-in-law to a restaurant for a meal,

This restaurant used to be a place my wife and I often visited.
When the owner served the dishes, he greeted me,
And said, "Didn’t bring your wife today?"
I was about to answer,
When my sister-in-law slapped the table,
Shouted loudly: "I am his wife, who are you talking about?"
The owner was stunned, and immediately stepped back.
I looked embarrassed and asked my sister-in-law why she was joking like that,
She said, "Just wait and see."
After finishing the meal and paying the bill,
The owner whispered: "Sorry, brother, this one’s on me!"