1. Only when the people here have betrayed me, I only really left the school.

2. For the well-organized mind, death is but the next great adventure.

3. This boy will be famous. There won't be a person in our world who doesn't know his name. —— Prof. McGonagall

4. If the monster existed, it was buried deep within. —— Albus Dumbledore

5. Be brave, professor. Be brave like my mother.

6. We are only as strong as we are. —— Albus Dumbledore

7. Never trust anything that can think for itself if you haven't seen where its brain is hidden.

8. People only waste time in front of a mirror that won't give them knowledge or truth. —— Albus Dumbledore

这些句子都体现了哈利波特系列中的主题和情感，包括勇气、友谊、爱与牺牲、以及面对死亡的勇敢态度。希望这些签名能够满足你的需求。