In the movie, Arwen tells Aragorn:
Ú i vethed...nâ
i onnad. Boe bedich go Frodo. Han bâd lîn.
Si peliannen i vâd na dail lîn. Si boe ú-dhannathach.
Ae ú-esteliach nad... estelio han. Estelio
Translation: This is not the end.
It is the beginning. You must go with Frodo. That is your path. It
is already laid before your feet, you cannot falter now. If
you trust nothing else, trust this. (meaning the Evenstar jewel)