"I will never forget anything again."
Translation:Ich werde nichts wieder vergessen.
It sounds strange. It means: there is something that I will never forget again. That's not what the English phrase says. A better wording of that meaning would be "Irgendetwas werde ich nie wieder vergessen". To capture the correct meaning, use "Ich werde nie wieder irgendetwas vergessen" which would be a much more natural way of saying it than duo's solution.