The phrase "are confident of" can be substituted with a variety of synonyms that convey a similar level of assurance and belief. Some options include "are certain of," "trust in," "have faith in," "believe in," "are convinced of," "have no doubt about," "are assured of," and "have a strong conviction about." These phrases all indicate a strong sense of confidence and belief in a particular outcome, decision, or action. Using synonyms for "are confident of" can help add variety to your writing and more precisely convey the level of assurance you want to express.