Don't fear the reaper = Noli timere messorem. That's a literal translation and a good Latin sentence, but it would not carry the English meaning.Don't fear death = Noli timere mortem.
messor, messoris
In hiragana: しにがみ In romaji: shinigami I'm sure the next poster will give the kanji.
"Koori no karite" is pronounced KOH-ree no kah-ree-teh.