Who plays 'that other woman'?

Hi friends...i have been a silent visitor of this forum so far...but, today i wanted to share a doubt of mine with you all...

somehow, i have this feeling that 'that other woman' was Khushi's biological mother...Garima's sister and that she resembled Khushi....I got this feeling when they showed a 'veiled' face of the woman who had come at the last darshans of Arnav's father...otherwise, it would have held no significance at all...

Garima is hiding from Dadi...because otherwise, she would have had to explain/justify things to Dadi...which she wants to avoid till the marriage...