Definition of ascertaining:
(v) :
(transitive) To find out definitely; to discover or establish.
(v) :
(intransitive, Yorkshire, dated) To look for something lost.
(v) :
(transitive, obsolete) To make (someone) certain or confident about something; to inform.
(v) :
(transitive, archaic) To establish, to prove.
(v) :
(transitive, archaic) To ensure or effect.