I Want to Become a Hard Persimmon (2007)

In both series the boy has a weak character and is dominated by a strong-willed girl.

Both are about bullied boys that are ... hopeless ... then the punk girl comes in and changes him, both very good love stories , but I find "Hi my Sweetheart" much more enjoyable to watch

Both deals with a bullied guy trying to become stronger and overcome the bullies.Both are set in high school