The girl had always been proud and confident in her skills. She had always been sure of herself.
She was considered the strongest fighter in the village. Both her sisters and the inhabitants of the village could always depend on her.
But all of that immediately changed the moment she laid eyes on the boy. It was the first time she had been defeated in a show of strength, after all. Since then the image of the boy had always lingered in her mind.
Even after the boy hurt him and broke his promise, the girl was still unable to be angry with him or harbor any feelings of resentment. The girl simply just loved being with him, so she decided to make a silent promise with herself to always stand by his side.
Later on, she realized she was not the only person on his mind. The boy showed her the beautiful, regal princess he always talked about, and the girl suddenly felt a different kind of anger.
Hope this explains her behavior. I have been keeping this for a while it's glad to finally tell you all why she always seems irrational