I am very surprised with Naina's dialogue

She said yesterday thay she can do anything for Sameer. Seriously?? She left Sameer and was going to marry Sharad few days ago. The reason she broke the marriage because Sharad humiliated Chacha ji. I am surprised with the writers. Please have some correlation. One day she just calls Sameer, break up without any proper explanation. She shows up in college with Mehendi in her hand. Sameer could have taken his life too!! She was never there. Now as Chacha ji supports, she is saying I can do anything.