So I compared their japanese handwriting (as in English, the fonts were the same)-
If you can see, MC's one is a bit casual, like her curves of the letters are visible, while Kasumi's is a bit on the sharper side, like all his dashes and lines are straight. No wavy letter at all. Nonetheless, both are so pretty.
This defines his strictness and discipline, and MC's determination along with her softness to achieve that.
*If only I can also get their English handwritings*













