Basically , the skeleton of all kams r the same so I am guessing Farhad gives it to her and and returns it n asks for a promise to move on...
In kam2 the hero had some pearls from the heroine as her only memory. He returns it to her (to her sister ) telling that one day she will return these pearls if his mohabbat has any value to her. She does it ..when she sees him in a miserable state , working as a labourer , she returns the pearls n asks for a promise to move on as she felt guilty to put him in that condition..towards the end, she falls sick, he had to be called , she looks at him and smile and die..n the hero also dies with the pearls in his hand..I guess in each season they use one such accessory.
If that’s the case then I think they’ll both die and it’ll end with dunya dil lagane ki jagah nahi hai, I’m looking forward to how everything unfolds