to testify

https://tts.langeek.co/read?text=dG8gdGVzdGlmeQ&hash=7b52224039bb171b036ee303dcc33555b37d6b65&lang=en&cache-only=0&driver=googletts

Here you will find the vocabulary from Unit 9 - 9E in the Insight Upper-Intermediate coursebook, such as "testify", "assess", "demonstrate", etc.