most surely believe, fully know (persuade), make full proof of

Strong’s Dictionary of Greek Words:

Number:
4135 (find all occurrences in KJV Bible)
Greek:
πληροφορέω
Transliteration:
plerophoreo
Phonic:
play-rof-or-eh’-o
Meaning:
from 4134 and 5409; to carry out fully (in evidence), i.e. completely assure (or convince), entirely accomplish
KJV Usage:
most surely believe, fully know (persuade), make full proof of