Some relevant words:
Estel hope
Penim I have not
Bannen lost
Savo amdir have hope (wrong kind of hope, though)
Penestel hopeless
Best I've come up with so far is:
Penim bannen estel I have not lost hope
Penim Penestel I have not hopelessness
Translations with dictionaries alone are almost guaranteed to be gibberish.
I'd say something like Allu líthannen estel, lit. "Never have I lost hope," using neologisms allu and lítha-.
Thanks!
I fully understand the overwhelming weaknesses of the dictionary approach! I'm just really having trouble with key sindarin language concepts, it's not sinking in. The pronouns often seem to be (somehow) embedded in the verbs and it's still greatly confusing me.