In the book it’s a conversation on the stairs of Cirith Ungol. In the book, Frodo is a strong character. In the movie, he is weak. It’s a light hearted section that Jackson turned maudlin. He did the same to the scene where Sam walks into the lake.
Faramir was mischaracterized as well. Also, Pippin and Merry were made out to be clowns in the movie.