Robert Pattinson is opening up about his deepest, darkest fear: being humiliated onscreen. The “Twilight” alum and “The Batman” star said while in conversation with Jordan Firstman for Interview magazine that there are no excuses for a poor performance. “I have a deep, deep fear of humiliation,” Pattinson said when asked if he ever took on a role that he did not believe in. “And also, you sort of know it’s down to you. You can say it’s a shitt…