Can you fall in love with you own brother?
Yes, but only if he isn't your biological brother.
In fact, the parents, after they have had him, the son, they had tried to have another child but they didn't have success, so they decided to adopt one, a beautiful girl with big brown eyes.
They grew up like siblings, but the love she felt for him was more than a sibling love, and she noticed it when he took home his first girlfriend. She tried to deny it, but everytime it was more evident: so she decided to date her brother's "enemy". This will make him feel jealous, and he will start to ask himself if his sister is only that or something more.

"And to think that before between us it was like a blood tie"- he said while kissing her head.
"Blood ties?"-asked she turning toward him.