Here are some quotes about not being good enough that I found:

- “The way you speak of yourself / the way you degrade yourself / into smallness / is abuse.” — Rupi Kaur.
- “I did the best I could, and in some arenas, my best was not good enough.” — Amy Grant.
- “Don’t let anyone tell you that you’re not good enough. You are good enough, but you have to work hard.” — Princess Diana.

I hope these quotes help you. Let me know if there's anything else I can help you with.