The spelling of the word "Theresha" can be explained using IPA phonetic transcription. The first syllable "The" is pronounced as /ðə/, followed by the letter "r" which is represented as /r/. The next syllable "sha" can be transcribed phonetically as /ʃə/, which represents the sound of "sh" followed by a short "uh" sound. Therefore, the correct spelling of this word would be "Theresha" /ðə'rɛʃə/. It should be noted that this word does not appear to have a known meaning or origin.