sinceramente
/sinˌθeɾaˈmente/ · B1 · adv
honestly
🫶 sincera + mente = with a sincere mind, i.e. sincerely
Spanish -mente works like English -ly: it turns the feminine adjective sincera into an adverb. It comes from Latin mente, meaning with a mind, so sinceramente is literally with a sincere mind. Same pattern: rápida + mente = rápidamente.