Actually, Gu Shuxin wasn't wrong.
When she lived with the Gu family, she had indeed acted as Gu Zifan's older sister. Back then, the Gu family had considered letting her take the place of their lost daughter, so they hadn't objected.
However, Gu Shuxin's mistake was mentioning the word "sister" in front of Gu Zifan now.
"No! You're not my sister! You're not my sister!"
Gu Zifan's voice was filled with defiance. His face was etched with anxiety, as if he were rejecting her words with his entire being.
"Fanfan, how could I not be your sister? I'm Sister Ke'er!"
Gu Shuxin hadn't expected Gu Zifan to get so agitated, nor had she considered what negative effect her words might have on him.
By the time she finished her sentence, Gu Zifan's expression had grown much uglier.
"Gu Shuxin, shut your mouth!"
