Oh, no, I'm engaged to a Douglas fir.
2 seconds sound clip from the The Last Unicorn movie soundboard.
You can hear this line at 00:39:19.289 in the Blu-ray version of the movie.
Quote context
[...]
- Oh. Oh. Oh, I love you. I love you. Love love love love love love love love love.
- Always, always. Faithfulness beyond any man's deserving.
- I will keep the color in your eyes when no other in the world remembers your name.
- There is no immortality but a tree's love.
- Oh, no, I'm engaged to a Douglas fir.
- Help, unicorn, where are you?
- Ooh, galls and fireblight! She shall never have you, the hussy! We will perish together!
- Did you see me? Were you watching, did you see what I made?
- Yeah. It's gone now, but I had it. It had me, but it's gone. I couldn't hold it.
[...]