"Oath"

This is a homophone clue - look for indicators like 'we hear', 'sounds like', 'say', 'aloud', or 'reportedly' - the answer sounds like another word

Break down the clue into definition and wordplay parts

Answer: STREWTH | Definition: 'Oath' | Wordplay: sounds, with an Australian accent (“would Aussie say”), like: ‘s truth = is truth =”not a pretence”