I'm saying this because if u notice in the new promo which is on air right now, Taani isn't wearing sindoor or anything, but in the first epi she had sindoor....so if thats the case then Onu and Taani must have married again after his return from USA, which is highly doubtful because Onu has a girlfriend and will probably not marry Taani...because if he did, the story would've ended..
so the only possibility i see behind Taani's sindoor is her marriage to someone else..
and do you remember she says she has come to know about him being in the mental asylum just today and the asylum lady tells her that Onu is in the asylum since 3 years...now if they were married again and the sindoor belongs to Onu, why would a wife not bother where her husband was since 3 years?