The court can consider any relevant factors, including your history and your past relationship.  For example, if you have never been violent in the past, it is less likely that a reasonable person with whom you shared a relationship would be terrorized by a playful threat.  The rationality of the statement could also be important.  People make exaggerated statements all the time.  If there was no reasonable basis for anyone to believe you would follow through, that could form a valid defense.