True North is something I made up! One of Cupid's symbolic things is the Northern Star. Both from biblical themes and "Evangeline" from princess and the frog.

Cupid is a cherub, and those are seen as protectors. Guardian angels, kinda!

She's seen as "true good" or a symbol of heaven. Heaven is often seen as the "true home" within religious circles, so people believe that Cupid is capable of guiding people to be a pure version of themselves, and thus allowing them to get through the pearly gates. The full quote is "For she is True North, I pray my soul follow her home."