The phrase "declare yourself to be" has several synonyms that can be used to convey the same meaning. These include "affirm," "assert," "avow," "proclaim," "state," "pronounce," "attest," "depone," "profess," "aver," and "utter." Using any of these synonyms can add variety and clarity to your writing or speaking. For example, instead of saying "I declare myself to be guilty," one could say "I assert my guilt" or "I profess to be guilty." By experimenting with different synonyms, you can create a more dynamic and engaging language that captures your audience's attention.