Complex sentence: Unfortunately, Kantarou decided for a different kanji for Haruka's name, as he thought Haruka was physically lovely, changing his name meaning' spring flower', which Haruka reckons sounds more like the name of a female combat fighter.
Split into simpler sentences: Unfortunately, Kantarou decided for a different kanji for Haruka's name, as he thought Haruka was physically lovely. The new characters change his name to mean' spring flower', which Haruka reckons sounds more like the name of a female combat fighter.