Making a declaration means stating something openly and formally. There are several synonyms for this phrase, depending on the context and the level of formality required. For example, you could say "announcing," "proclaiming," "asserting," "pronouncing," "avowing," "affirming," or "declaring." These phrases convey confidence and conviction, and show that you are willing to stand behind what you are saying. Other synonyms for making a declaration include "stating one's position," "making a public statement," or "putting forth a proposition." Whatever phrase you choose, be sure to speak clearly and forcefully, so that your message is heard loud and clear.