This is probably not a thorough reply, I am just going to first write down my initial thoughts. And maybe afterwards will go more into the stuff I'm probably missing.
I will first start with pointing out that Mohan was/is NOT going about this as he should in an arranged marriage. As I said before, I will never let this pass without my bringing this up. Just because one is an arranged marriage doesn't mean there shouldn't be an effort at understanding, knowing and expecting to love the other person.
Are there bad or less than ideal marriages, yes. But there are love marriages reality comes up and the marriage becomes less than ideal. (Though, is any marriage ideal?)
Mohan has not been trying to do any of these things. He's just happy going around treating Kastur more like a friend, never putting an effort in seeing her as his eventual romantic partner. And living abroad is not an excuse, either. If that were the case then many of the kids who grew up in the States, to go India to have an arranged marriage--none of them should be okay now. Are there marriages that don't work? Yes. Both arranged and love. But I've also seen the ones that work, and how the people go about it, and what their mindset is,
Mohan's mindset is nothing like those who would agree for an arranged marriage. And just because there are those who go around in real life that don't take it as they should, doesn't mean they are right or Mohan is right.
Mohan's (inebriated) desire to share his happiness with his wife is all well and good. I don't know how many times on this board I've said, don't take into account anything a guy declares while intoxicated. However, Kastur has no reason to believe Mohan doesn't love her. Because in her mind, he's known this just as she had known. She is a 19-year-old girl, who even without this would get her hopes up and fall so easily with what she had seen in an inebriated Mohan. But even without that, consider her own experiences.
Mohan comes and blasts her. She gives him the chance to back out. What does he do? Says he was testing her. He could've been "somewhat" truthful (I know why he wasn't and understand why but I'm saying this as a hypothetical) and tell her he hadn't known till now, and his reaction was out of shock. But now he's thought about it, and he's sorry... blah blah blah, some stuff.
But that's what what he said. And he hugs her. While you may think it's normal to hug friends, that's not normal in all circumstances and not normal in many stratas of Indian society (as well as other societies).
And again and again, more and more instances pile up. How she told him, "I know you're not marrying me for money, I don't doubt your love/feelings." The times when he asked her if she trusted him. All those are connected with some feelings of love, especially in their situation. Why should she not believe that he also had similar feelings of love?
As for love. Love is complicated. I don't think Kastur's love is unreal. Why do parents love their children right away (even if not biological)? Why do people love their pets? Why do I love my cat? 😆
Over time it may change in various ways. The love may even go away. But I don't think it should be discounted just because she'd loved him far away without knowing much.
Do I think all these are fairy tale dreams; and she shouldn't have been encouraged like this; she should need to experience reality rather than the dreams; she shouldn't have been groomed as a dharampanti, etc etc. Yes, I've said all that before.
But nevertheless, none of that discounts that there is realness to her love.