I remember it started as a one sided thing from Shalin and now it looks two sided, but i still feel Tina doesn't love him. She just enjoys the attention (like any other girl would). She thinks she is attached to him because he loves her .
I think she has been love bombed by Sha, From feeling nothing for him, to getting attached and attracted.
Love bombing in psychology is displaying overtly affection and attention and making grand gestures of love on victim to sweep them off their feet and make them dependent on them so that when you start withdrawing the love and affection, it starts feeling like a drug withdrawal for the victim. Commonly used by narcissists to make their victim fall in love with them.
I also don't find her to be this evil or cunning person that everyone finds her to be . Yes, she is definitely not naive, on the contrary She is very clever and opportunistic , but i don't think she is evil.