Although some people call their girlfriend "sister-in-law," using this term indicates a pretty close relationship between Bo Yan and Xia Siyu. If a man likes a woman, you can tell by whether he introduces her to his social circle. Introducing her at least shows that it's more than just a fleeting romance; he's starting to make her a part of his life in various aspects.
A few friends clearly understood and immediately called her "sister-in-law."
Xia Siyu retorted, "What 'sister-in-law'? You should call him 'brother-in-law.'"
She was not "Mrs. Someone" or "Madam Someone." She was Xia Siyu, and even when it came to her husband, he should be called "Brother Xia" rather than "Little Sister-in-law"!
The group of people nearby laughed even harder, "Alright, sister-in-law, we're taking brother-in-law away."
With everyone getting their own fair title, Xia Siyu stopped making a fuss.
