Their feelings were mutual and they can see it in each other's eyes.
when u love someone u start trusting him too and if at any point u come to know that the person has lied to u that will be a g8 shock for any one.
One point which is making her feel like this is when Arjun told her to leave she said "I love u Arjun" without knowing about him. And now she is thinking in the way that he just used her to get his father out of bars that's y she is saying that i will never forgive u Arjun.
Her condition is obvious but soon she will realize the fact and accept the truth.