In one scene Yvaine asked Tristan:
"The little I know about love is that it's unconditional. It's not something you can buy... You did this (finding a fallen star) to prove your love for her. What is she doing to prove her love for you?"
Later, she confessed to Tristan:
"You know when I said I knew little about love? That wasn't true. I know a lot about love. I've seen it, seen centuries and centuries of it, and it was the only thing that made watching your world bearable.
All those wars, pain, lies, hate... made me want to turn away and never look down again. But to see the way that mankind loves…. You could search to the furthest reaches of the universe and never find anything more beautiful.
So yes. I know that love is unconditional. But I also know that it can be unpredictable, unexpected, uncontrollable, unbearable and strangely easy to mistake for loathing, and...
What I'm trying to say, Tristan is... I think I love you.
My heart… it feels like… like my chest can barely contain it. Like it doesn't belong to me anymore. It belongs to you. And if you wanted it, I'd wish for nothing in exchange - no gifts. No goods. No demonstrations of devotion. Nothing but knowing you love me too. Just your heart, in exchange for mine."
Lovely. And yes, I've finally learnt that girls only confess their love in the movies. In reality, it's the guys that ought to make that first move. I guess one doesn't need a scientist to teach him that. Or maybe he does.