Rein is a German word, in English means pure. The opening lyrics start with „Sieg Heil“ and „reines Reich“ which is pure (plural possessive in German), kingdom. Near the end of the song, it is sung „Seig Heil“ slowly, with bells as in church bells ringing. That part of the same is my favorite part of the song, I feel intense racial pride for the Aryan race which feels hypnotic and and ancient sense of belonging. Similar to when I saw a swastika flag in the Museum of Flight in Seattle.