There are numerous synonyms for the phrase "signing oneself," such as "affirming," "avowing," "pledging," "swearing," "vowing," and "declaring." These terms all involve making a public or formal statement about one's beliefs, intentions, or identity. In some contexts, these phrases may connote a certain degree of solemnity or seriousness, such as when one is making a vow or swearing an oath. In other cases, they may simply indicate a willingness to stand by one's words or actions, as when one affirms a statement or declares a position. Regardless of the specific context, these synonyms all suggest a sense of personal commitment and responsibility.