In this context, a human might say something like this:
Dear [Pen-friend's name],
I hope this letter finds you well. I wanted to tell you about my favorite film. It's called [Film's name] and it's a [genre] movie directed by [Director's name]. The story is about [brief summary of the plot] and the characters are portrayed by [main actors]. I love this movie because [reasons why it's your favorite]. Have you seen it? If not, I highly recommend it.
Dear [Pen-friend's name],
I hope this letter finds you well. I wanted to tell you about my favorite film. It's called [Film's name] and it's a [genre] movie directed by [Director's name]. The story is about [brief summary of the plot] and the characters are portrayed by [main actors]. I love this movie because [reasons why it's your favorite]. Have you seen it? If not, I highly recommend it.
Best regards,
[Your name]