Guys I know we are all feeling sad, even me, but this might be a better solution, it's better than Sana going on and then her health takes turn for the worst and she quits anyway later.
Ariya LS didn't even start yet so it will be easier for us to accept someone else for Arjun later.
The possibilities are endless on how they can bring a love interest for Arjun.
I am sure they have it planned out so the show doesn't lost its appeal.