вы моя единственная

you are my only…

→ вы
phrase Rare #45,139
you are my only… “Вы” can address one person politely or more than one person. “Единственная” agrees with a feminine noun that follows or is understood from context.
RU: Вы моя единственная надежда.
EN: You are my only hope.

И вы моя единственная семья.

And you are my only family.

— История Дэвида Копперфилда (2019)