Sentence:  Therfore the saide cõmissioners shall mowe say that nowe late during the parlement the King <WSD>ascertaigned</WSD> of the saide maliciouse prpose of his enemys, willed and desired the lords being then present to shewe their̃ good willes aide and helpe for the saide rescues... 
Meaning of the word marked with <WSD> tags:  To make (someone) certain or confident about something; to inform.