The spelling of the word "Acacin" can be explained using IPA phonetic transcription. The first syllable "aca" is pronounced as /əˈkɑː/ with a schwa sound followed by the long "o" sound and the stressed "a" sound. The second syllable "cin" is pronounced as /sɪn/ with a "s" sound followed by the short "i" sound and the "n" sound. Therefore, the correct spelling of the word "Acacin" is a-c-a-c-i-n with the stress on the second syllable.