What is the religious ruling regarding my brother, who sexually assaulted me when I was five years old, and will I be punished for my feeling of hatred towards him?

If what you mentioned happened between your brother and you, then he has sinned greatly, for adultery is forbidden, and committing it with maharim (unmarriageable kin) is even more heinous and strictly forbidden. There is no blame upon you for disliking him because of his action. If you still feel suspicious of him, then you must be cautious of him and treat him like a stranger; do not allow him to be alone with you. However, if he has repented and you no longer feel suspicious of him, then you should try to forget the matter and treat your brother as if nothing had happened.