This is the 14882nd most frequent German word.
reines
"Reines" means "pure" or "clean" in English (used as an adjective).
In this context, "reines" modifies the noun "Quellwasser" (spring water), indicating it is uncontaminated or free from impurities.
Das Wasser in der Flasche ist reines Quellwasser.
The water in the bottle is pure spring water.
The word "reines" describes the quality of the noun "Vergnügen" (pleasure), emphasizing that it is unmixed or purely that.
Das ist ein reines Vergnügen.
This is pure pleasure.
Here, "reines" characterizes the noun "Herz" (heart), signifying clarity or moral purity.