Assert is a powerful word that means to state or declare something with confidence. There are several synonyms that can be used in place of this word, including affirm, maintain, declare, claim, state, contend, and proclaim. Affirm is commonly used to assert the truth of a statement, while maintain emphasizes the endurance and persistence of the assertion. Declare and claim both suggest making a definitive statement or claim, while state is more neutral in tone. Contend and proclaim both suggest a forceful and determined assertion, although the latter may have religious connotations. Regardless of which synonym you choose, each carries the weight of a strong and confident statement.