My favorite one is:
Duke the Lorca:
Next time I cut more deeply.
Don Juan:
Next time I wear my old clothes. (I love that change of expression for looking worried to that great smile and deliver that great unforgettable line)
Don Juan:
My dear friend, there’s a little bit of Don Juan in every man, and since I am Don Juan, there must be more of it in me!
Don Juan:
The sword is not for a traitor. You’ll die by the knife!
Don Juan:
Catherine, an artist may paint a thousand canvases before achieving one work of art. Would you deny a lover the same practice?
Don Juan:
Beloved, no power on Earth could’ve kept me from you. In all the world there’s been but one image in my heart, one vision before my eyes…
Catherine:
Yes, yes, go on…
Don Juan:
I have loved you since the beginning of time.
Catherine:
But you only met me yesterday…
Don Juan:
Why, that was when time began!
Catherine:
But how long will you love me?
Don Juan:
Sweet lady, love is not measured in terms of time, only in ecstasy!
Duke de Lorca:
May I remind you, my dear fellow, that in a conflict one must choose a side. The middle ground is frequently the most dangerous.
Don Juan:
I’ve been in the middle so many times, your grace… it doesn’t disturb me.
Don Juan:
A man gives up everything: a rich full life and the first time he tries to be utterly sincere, what happens?
Leporello:
That’s exactly what I’m trying to find out.
Don Juan:
Well, mind your own business!
King Phillip III:
We consider Don Lorca the greatest living duelist in Spain.
Don Juan:
That’s certainly the mark of a good duelist, you majesty – to be living.
— Don Jan