The phrase "am of the opinion" is a common way to express a personal belief or viewpoint. There are several synonyms that can be used instead of this phrase, including "believe that," "think that," "maintain that," "hold that," "assert that," and "contend that." These synonyms convey the same meaning as "am of the opinion" but can add variety to your writing or speech. Choosing the appropriate synonym will depend on the context and tone of your message. Regardless of which synonym you choose, it is important to communicate your beliefs or opinions clearly and effectively.