Wait, maybe I should check if there's more to the story. I remember that there's a subplot involving Arjun's childhood friend, which might be a love interest he had in the past. Maybe this is where the conflict comes in. But how does that tie into the main story? Also, the title suggests that the heart is still a child, meaning that despite external circumstances, love remains pure or untainted, which the movie probably explores through the characters.
I think there's a part where Pia and Arjun go on a trip to London together, which is when she learns the truth about their parents' plan. She might then decide to end the marriage temporarily but later reconcile because they have grown to love each other. The resolution would involve them overcoming their parents' expectations and choosing a life together.
Arjun and Pia, both strangers, are married under pressure from his family, who insist the union will mature him. Their initial interactions are strained—Arjun treats Pia as a transactional partner, while Pia resents being a pawn in his parents' game. However, during an arranged family trip to London, they share a quiet, emotionally charged moment that sparks genuine curiosity between them.