When it comes to expressing certainty and confidence in a statement, there are a variety of synonyms to choose from. Some strong options include "asserts with conviction," "declares emphatically," "avows firmly," "states categorically," and "insists assuredly." These alternatives to "affirms with confidence" communicate a sense of unwavering belief in what is being said, as well as a willingness to stand by the statement in the face of any challenges or doubts. Whether you are making a bold proclamation or simply conveying a strong opinion, using one of these synonyms can help you communicate your message with clarity, precision, and unwavering confidence.