We don't when it happened. And when he recognizes it, he only expresses it to himself in terms of a competition ("i will make geet confess he love for me" " I will make Geet do this" "Geet will have to...")
And before that all we saw was attraction, on a physical level and level of curiosity.
Afterwards we see his concern for her. He wants to be her savior and protector. He sees her innocence and helplessness.... which is all fine, Mann out to be a hero..... BUTTTTT now we see exactly where this has taken him...his EGO has come out.
What about why Geet his important to him? Why can't HE live without her? What does she do for him? (I think i can answer this somewhat, but I'd rather criticize Mann first before defending him).
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