Italian word certamente comes from Italian -mente, Italian certo

Detailed word origin of certamente

Dictionary entry	Language	Definition
-mente	Italian (ita)	(productive) Used to form adverbs from adjectives; -wise, -ly, -ally.
certo	Italian (ita)	(preposition) some, certain. Certain, sure. Reliable Certainly, of course, surely, definitely.
certamente	Italian (ita)	Certainly, definitely, surely, of course.

Words with the same origin as certamente