sîr law navon dúath tolen darthed
Sîr law navon Dúath tolen darthed
Sîr - "now, today"
law navon - "not I judge" (I had to look up for the context to pick from "feel", "reckon" or "hope", but seems to me Faramir rather said that with confidence, so I chose "judge" instead)
dúath - "darkness, night-shadow" (Tolkien used it metaphorically for darkness as an ethereal substance, the opposite of light - I felt it was more appropriate than môr here); since Sindarin doesn't have a word for "some, any", I thought that an indefinite article would suffice
tolen darthed - "comes staying" (one of the forms of future tense)
I'm not sure how accurate this is, but hope this helps.