When you fall in love with someone, it isn't planned by you. it just happens, in the first stage you don't pay attention to thier faults, you just want to be with him/her.
Now after sometime you start seeing the differences. Bisma and Hashir love each other. now they are realizing the matters which come with love. the differences in their personalities.
I completely agree. For a long time you will believe they are perfect but then much later on you will see their negative qualities; which isnt a bad thing depending on the person