Believing in something is an inherent quality of human nature. However, sometimes we need to express our belief in a more assertive and firm way. Some synonyms for the term "be a great/firm believer in something" are trust, have faith, rely on, count on, have confidence in, have conviction in, put one's faith in, and have a firm belief in. These terms represent the same level of strong belief in something and reflect the individual's confidence in their beliefs. A person can use any of these synonyms to emphasise their conviction towards a particular concept, belief or idea. Such synonyms provide an excellent way to convey our conviction to others and make our voice count.