Strong's G1226 — διαβεβαιόομαι (verb)
diabebaioomai (dee-ab-eb-ai-oh'-om-ai) v.
1. to confirm thoroughly (by words), i.e. asseverate
[middle voice of a compound of G1223 and G950]
KJV: affirm constantly 
Root(s): G1223, G950 
Hebrew root: βεβαιόω
Occurrences: 2