Adverbs of affirmation (advérbios de afirmação) and adverbs of negation (advérbios de negação) are some of the most essential words in all of the Portuguese language (and, indeed, any language). They are always invariable, so no need to worry about different variations or uses. For English speakers, they are incredibly straightforward to learn and sometimes even to guess.
Adverbs of affirmation are, as the name implies, words which declare that a given statement or fact is true, or “positive”. They include:
Certamente is the Portuguese equivalent to “certainly” or “for sure” in English.
Estás a perguntar-me se quero gelado? Certamente! You’re asking me whether I want any ice-cream? For sure!
Esse é certamente um bom motivo. That is certainly a good motive.
Adverbs of negation, on the other hand, declare that a given statement is false, or “negative”. They include: