[LadyBrooke]

These might not be good suggestions but I can tell you what are some Quenya and Sindarin words that might work.

Voronda and vórima are faithful in Quenya, while sadron means faithful one and sedryn means faithful ones in Sindarin. Of the four I think sedryn sounds the best but I'm not sure if this is something along the lines of what you're looking for or not.