The spelling of the word "Hennreitta" can be explained using the International Phonetic Alphabet (IPA) transcription. The first syllable, "Hen," is pronounced as /hɛn/, with the "e" sound as in "bed." The second syllable, "nei," is pronounced as /neɪ/, with the "ai" sound as in "came." The final syllable, "tta," is pronounced as /tə/, with the "a" sound as in "comma" and an unstressed "t" sound. Therefore, the correct spelling of the word is "Henreitta" with only one "n" in the middle.