ellrond:

“But the Queen Arwen said: ‘A gift I will give you. For I am the daughter of Elrond. I shall not go with him now when he departs to the Havens; for mine is the choice of Lúthien, and as she so I have chosen, both the sweet and the bitter. But in my stead you shall go, Ring-bearer, when the time comes, and if you then desire it. If your hurts grieve you still and the memory or your burden is heavy, then you may pass into the West, until all your wounds and weariness are healed. But wear this now in memory of Elfstone and Evenstar with whom your life has been woven!’

And she took a white gem like a star that lay upon her breast hanging upon a silver chain, and she set the chain around Frodo’s neck. ‘When the memory of the fear and the darkness troubles you,’ she said, ‘this will bring you aid.”