The girl looks depressed and preoccupied all the time. There is no way to mistake it. Even Sanskar to some degree senses her distress, although he thinks it's about her father. He knows that Karan has feelings for her, and in the back of his mind, must know about Abha's love for Karan. In any case, it should not surprise him when Abha discloses it.
I've stopped guessing what the creatives will go next because they always surprise us, but it may not go all the way to the wedding.