The correct spelling of the phrase "wast about to" is actually "was about to". The reason for this is that "wast" is an archaic form of the verb "to be" that is no longer used in modern English. The correct pronunciation of "was about to" is /wʌz əˈbaʊt tu/, with the stress on the second syllable of "about" and a short vowel sound in the first syllable of "was". It is important to use correct spelling and pronunciation in order to effectively communicate in written and spoken English.