I don't think I could change her back even if you wished it.
3 seconds sound clip from the The Last Unicorn movie soundboard.
You can hear this line at 01:22:12.186 in the Blu-ray version of the movie.
Quote context
[...]
- Lir, I will not love you when I am a unicorn.
- Then let the quest end here.
- I don't think I could change her back even if you wished it.
- Marry the prince and live happily ever after.
- No. Lady, I am a hero, and heroes know that things must happen when it is time for them to happen.
- A quest may not simply be abandoned.
- Unicorns may go unrescued for a long time, but not forever.
[...]