Her side of the story.
In the high school, I had a classmate who I really believed he loved his girlfriend. One day, they suddenly broke up their relationship. When I asked him what was the reason for the splitting, he said it was because she had cheated on him. However, I heard others classmate say that, in her side of the story he is the one who had cheated. I believed he is the one who was telling the truth. Unfortunately, it's not what others thought.
*I added splitting instead of break up, to avoid repetition.
I tried to keep changes to a minimum, but I had to tinker the text a little bit.