Mark's words disturbed Shang Jiao a little bit, actually, quite a lot because she had never imagined Ji Guanli in that way.
However, she had been friends with Ji Guanli for more than a decade and treats him just like her own sibling too. On the other hand, she had only found out that Mark was her real brother, just a day ago.
In the end, the decade-old friendship won over her immediate thoughts and she assumed that her brother was probably trying to draw a wedge between her and her friend because of his enmity with Ji Clan.
But, at the same time, she cannot refute his words as well. In the end, she decided to confirm herself with her friend directly and also give him clarity on her opinion in case he misunderstood her supporting actions for love.