Many people have been asking... so i thought i'll explain.
All of us know Jaswant [Preeto and Seebo's Dad]... originally, he was supposed to marry Santo as she loved him a lot. But he fell in love with Shibani [Preeto and Seebo's Mom]... Before they could get married, shibani was found pregnant, which is why veer singh hates shibani and her daughters.
When santo finds out that jaswant loved shivani, she comitted suicide by burning herself in the room. Ever since, there has been a lot of hatred between the two families
Hope that was a good update and that everybody understood😳