Urmi's Mom knew something was amiss during this whole wedding.
She changed her mind when SamRAT brought his mother to apologize .
She knows for sure that Urmi will have trouble from her M I L.
Trishna spilling the beans to her will now really worry her but I do not think she will do much about it because she may be a worrier but does not have the guts to stand up to SamRAT and his family and want her daughter out of that situation.
Urmi has had a niggling feeling but her overall dream of her wedding and constant reassurance from her family and Ishaan had lulled her into believing that all will be fine.
She will wake up soon and realize that her dream is going to turn into a nightmare.