I am just wondering why Karan didn't ask her complex questions of the law? We don't see him having the mystical power of love to magically see Abha. Why no logic? Karan is a lawyer.
This is the train of thought he should have had:
How can I prove definitively which one is Abha?
Scientific evidence (fingerprints and DNA) or unique identifiers of Abha (her knowledge and personality)
Can I be sure of the results?
If Abha and Albeli are twins (which is likely because identical people is statistically impossible) then their DNA is identical but their fingerprints are not regardless of being twins or not. Testing for fingerprints is simple but can be easily tampered with by Albeli and/or Priyanka given means.
How about her unique identifiers (ie. personality, knowledge, or personal experience)?
Witnesses Jhumru and Mama state they dropped Abha#2 on Priyanka's behest. Assuming true, Priyanka would have prepared her for pretending to be Abha with everything she knows except for that beyond her knowledge.
Abha#2 states that she has been gone for 4 months. Assuming true, this means that Abha#1 has been masquerading as real-Abha for 4 months which is a significant time for her to obtain secrets she shares with home, family, and Karan. Thakur Sab's book excaberates this problem. The fact that Abha shares any secret or experience with any family member means fake-Abha could have gotten that information from the family member or Priyanka's own investigations.
What is something fake-Abha cannot gain knowledge of without being Abha?
Knowledge not disclosed by family or Karan off-handedly to other family, outsiders, Priyanka or fake-Abha masquerading as Abha for 4 months... AND THE LAW!
Conclusion: Fake-Abha has a vast knowledge of Abha in both scenarios although limited, but how limited is hard to qualify. Not only that, if Priyanka has conspired this or anyone else for that matter, she has a network to help support her in faking being Abha and that can mean evidence-tampering, fake testimonials, etc. Given the information that Albeli is a dancer and not highly educated, complex questions about the law (not easily learned in 4 months) will easily identify the impostor.
If on the off chance, Albeli is highly educated in the law, pretending to be a dancer, and knows this information, then I guess we could test in hundreds of labs for fingerprints... So many, that there is no way Albeli or her network could sabatoge all the results... Or Karan could finally deserve Abha and see it in her eyes... Even the prayer song that Albeli is so ignorant of would work! 😛