Arjun romances Sam only because she is a means to an end. He seduces her because that's the only way he will get to have control on her life. This is not love. This is revenge... and this revenge is never gonna turn to love.
On the other hand there is Ardhika. Kucch na karte hue bhi, there is everything between these two. There is laughter, there is friendship, there is tenderness and there is that slowly creeping in love. Radhika does not even have to flirt with him. She just has to show up and our man is ghayal to say the least. 😆