>>49852964
>Is her heart just that pure?
Pretty much. She's also a really calmed person accordng to Rika, so that's why she nevers gets paranoid enough to trigger the syndrome.
In fact she's the only one that never gets it (without counting Gou's garbage), as even Rika said that she succumbed some times in the past herself, which really makes me curious as how that would even go.