This was the star dialogue of the episode. It has a deep meaning. Zain was trying to convey that how much ever they will fight or defeat each other but ultimately they will have to live with each other. They cant run from each other bcoz they both wish to complete their story.
THE BEINTEHAA LOVE STORY!!!
They both somewhere have started enjoying each other's company. Love has yet not bloomed but they are becoming each other's habit. They both need each other not bcoz they love each other but bcoz they like to give defeat and get defeat. Habits are a very important part of life. Habits whether good or bad never goes easily. Other important highlight was when aliya took promise from zain that they will never hide anything from each other. And this promise show their trust on each other. Trust is an another important ladder towards love. They both are one so they cant hide anything from each other. Indirectly aliya has made zain so close by taking and giving this promise bcoz this promise shows the strenghth of their relation.
HABIT and TRUST are the two important things which they have already developed in their relation. Love doesnt seem far now.