"MNNCE" is not a word in English, and therefore has no standard spelling. However, if we were to attempt to phonetically transcribe it using the International Phonetic Alphabet (IPA), it might look something like this: /mə-nəs/. This would indicate the presence of two syllables, with some kind of vowel sound in each. However, without additional context or information, it is impossible to determine the exact pronunciation or spelling of this non-existent word.