It was such a pleasure to have the opportunity to discuss the possibility of an internship with your company. I know I can learn a great deal while working for you and your staff, and I have a great capacity to absorb new information and readily apply it to get the job done. If offered this internship, I’d like you to know that I will work hard to earn your confidence. I am a very competent, self-motivated worker, and within a short period of time I will be ready to embark on assigned projects with minimal supervision. Thank you so much for the interview. I look forward to the prospect of working with your company.
(YOUR NAME HERE)