Hanna wasn't originally a comic book. It could have drawn some influences from the comic book style or genre, but it has its own unique origin and story development.
Marin does confess to Gojo in the manga. It happens during a crucial moment when their relationship reaches a turning point. The confession is filled with honesty and vulnerability.
Partly. The core concept of Hanna might have roots in real-life situations, but the specific plot and characters have been fictionalized and elaborated to create an engaging narrative.
Nope, Marin and Gojo don't end up as a couple in the manga. The manga follows a different narrative path for their relationship, concentrating more on other aspects of the story and character growth.