Interesting interpretations, everyone, and I agree with a lot of it. However, I'm going to throw in an alternative interpretation which I think makes things even more interesting and complex:
- The singer starts off NOT in love with the target, but rather was planning to get into the relationship and break his heart as revenge for her friend (his ex-girlfriend). Thus, she states at the beginning that she "knows there's no point in trying to change you", but "unlike her I'm not about to let go so easy". (In my interpretation, this means that the ex-girlfriend has gotten over him, and is trying to forget, but the singer still wants revenge and refuses to let go of this matter of him being an asshole to her friend.) She further explains her plan in the first pre-chorus:
"As if I don't know anything,
Baby no more real love
I will stay by your side
Then in the end break your heart"
In other words, she's pretending to not know that he's a cheater (even though she does know), and is deliberately trying to get close to him in order to break his heart and make him feel regretful. She doesn't believe in real love - she's just doing it while masking her feelings of hatred: (i.e. "You don't know me, L O V E or hatred. Instead of goodbye I wear an innocent smile" - the guy can't tell that she's masking her hatred, and pretending to love him)
But then by the end of the first chorus and Verse 2, she finds herself losing her hatred of him, and finding herself wanting to forgive him. If you contrast Pre-Chorus 1 ("Baby no more real love... in the end break your heart") with Pre-Chorus 2 ("Just like real love... Show me your true love"), she moves from a cold hatred that disbelieves in love to someone who desperately wants the pretend-relationship to be real love.
This is further emphasised by an interesting conceptual twist in the Bridge: "Love is so toxic, it makes hatred melt away". This is fascinating because it's a reversal of how you would normally expect the word "toxic" to be used in a relationship. Here, LOVE is the toxin that destroyed her hatred, not hatred being the toxin that destroyed her love. She's mourning the death of her hatred, not the death of her love.
And so, the meaning of the line "cry for me" becomes complex and changes over the course of the song, from "CRY for me", to "cry FOR ME". In other words, at first she just wants him to cry, to show his remorse for being a "bad boy". But by the end, she wants him to cry FOR HER, to signify that he cares for her. Because then she finally has the excuse she needs and justification to outwardly let go of her hatred and enjoy the relationship. But if he can't, then she can't officially forgive him, and must make him die for her. *cue yandere vibes*