Everytime you fall in love, you lose a part of your soul to the person you love. Everytime someone falls in love with you, you get a piece of their soul. You die when you run out of soul to give
History only knows two immortals so far; Russia, who never found love; and USA, who makes people fall in love with her to purposefully extend her life...
She just got to find out that she can extend the other person's life too...
-"Tú no estás maldita, tú eres la maldición, los hombres se destruyen amándote"
...
-"Tú no me amas, no puedes amar de hecho, esa es tu maldición"
-"Eso creí, hasta que te ví"