firmemente
/ˌfiɾmeˈmente/ · B2 · adv
strongly
💪 firme + mente = firm + mind-ly, so a firmly set way of acting
Spanish adverbs add -mente to the feminine adjective: firme + mente. Think of it as the same as English -ly. Firme is related to English firm, from Latin firmus, so the meaning carries over directly.