White pearls are known as a symbol of purity and innocence and when a woman wears white pearls they represent her chastity.
Now Arnav questioned Khushi's purity and innocence when he accused her of having an affair with Shyam. So far, despite her numerous attempts Khushi has been unsuccessful of clearing her name.
After the Arnav's love confession Khushi dreams of Arnav putting white pearls around her neck therefore reinstating her chastity.
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