This word, meaning "filled with fear, apprehension, concern, or regret," is overused in everyday conversation with the verb to be as a loose, inaccurate synonym for "to think," "to feel," "to believe." Avoid such statements as "I'm afraid you're wrong" and "I'm afraid not," unless your concern, regret, or worry is strong and intense. In speaking and writing, do not use afraid unless you could equally well employ scared, apprehensive, fearful, frightened, alarmed, or terrified. In casual and informal conversation, afraid is often used either apologetically or in an attempt to soften or lessen an unpleasant statement: "I'm afraid I have bad news for you."
Dictionary of problem words and expressions. Harry Shaw. 1975.