Quote from : The Lord of the Rings: The Fellowship of the Ring Movie

Arwen: Do you remember when we first met?
Aragorn: I thought I had wandered into a dream.
Arwen: Long years have passed. You did not have the cares you carry now. Do you remember what I told you?
Aragorn: You said you'd bind yourself to me, forsaking the immortal life of your people.
Arwen: And to that I hold. I would rather share one lifetime with you than face all the ages of this world alone.
[hands him her pendant]
Arwen: I choose a mortal life.
Aragorn: You cannot give me this.
Arwen: It is mine to give to whom I will. Like my heart.