Gauri has her own charm! She had been in love with arjun and grown an emotion that Arohi did not experience until she herself is drawn to Arjun! However the difference remain that her feeling is reciprocal towards Arjun why Gauri was one-sided love! Gauri had quite advised her about love but Arohi then had her heart in control and shunned all her words by practical thinking of mind! Happen to be that even Shefali is the childhood friend of Arohi! She is light heartred,practical,cool,funny and then she is the one who has seen the transformation in Arohi from the girl who just talks from her reasoning to the girl who is melting in love! Shefali remains the one to understand what Arohi's state is in because she does not need to talk much. Lightly she earmarked her words to her! Now Gauri is arohi's chachi and I believe for the moment Shefali remains th buddy of Arohi! Gauri will understand Arohi much later when she realised that Rajveer is just the carboncopy character of Arjun. Also,like Gauri hid this from Arohi when she was in love, Arohi also will not be able to tell Gauri so quickly and will prefer to continue to share with Shefali as she had been the audience of the story and then there is Mishti too;)
So I am voting for Shef too!