There's a spark like connection here, one that pulls her closer and closer, makes her heart swell with so much affection, nothing else could compete, and his arms are so warm and so gentle around her, like a little pool of strength even when the world spirals out of control. And his lips as soft and sweet as they are against hers are almost addictive.
But the way he looks at her after they pull apart, the way he sees her and loves her for who she is, despite anything that could come between them is it's own special brand of addiction, it's own natural warmth. And how could she not long to press close, to kiss Zen back with so much pent up love inside of her that it overwhelms the both of them. How could she not, when he stares at her like that?
So softly that there is no harshness to the gaze, so gently as if they have forever just to press close and be by each other's sides. So warmly, that her heart fills up with warmth in unison with the gaze, and so fondly, that no matter what, he'll love her through it all: good times, bad times, almost impossible times, and more.
Just the love here is incredible, and a kiss might be a small way to return and showcase that love, but even so, Shirayuki leans forward, presses close, and kisses Zen back as if they have all the time in the world to share this moment together, to draw close, and just be together through it all, gently and with great perseverance.