It's not like he didn't expect it, as Zen was there when Shirayuki got the position, just there's a difference between knowing something and seeing it before you. Of course, getting to sit around the castle and say, 'hi,' to his friend that he knew he was sort of falling for was an added benefit to her working here, just there's something a bit more to it.
Zen doesn't really have any idea what he thought he'd see when he finally looked up and 'good morning' came out all jumbled. Just, there is Shirayuki, dressed up in her herbalist uniform, looking as if she belongs here, as if this is her home, her job, and something that she's always confidently sought. She belongs, despite what anyone else may say of the matter, despite what Lord Haruka had said about it before, despite the man that shot an arrow at her.
Shirayuki's badge came in, custom made, and the pink pendant swings when she shows it off. She's officially a member of the castle; she belongs here. This is her job, and no one can rightfully take her away from it.
It's a realization, an insight, into the fact that she will be here, a kind of permanence. She's not going to just one day up and leave Clarines, go back home to Tanbarun, since things were settled with Raji. Instead, it's a sign that she'll stay here, that she's made Clarines her home or more importantly this castle's her home now.
Beyond that, Zen can't help but think of those words that she'd said to him so long ago or at least it feels like a while since they left her lips, "I want to see how you live here in your homeland, Zen. So... I'm looking for a place where I can make that wish come true."
Her sincerity, the way that it hadn't just been mere words or an errant thought, but something that she'd taken her time to think through and come up with, stuck with him, lodged itself somewhere deep in his heart.
And in a way, seeing that pendant around her neck, said that she'd fulfilled that wish, but the other part of it wouldn't be filled with merely a title. The other part of that softly spoken wish would take years and heaps of memories piling up to come true. It's in it's own way, a kind of permanence, or a semi-permanence.
This feels much more permanent. Zen doesn't have words for this feeling that scampers in his chest, perhaps joy is a close counterpart or warmth or hope or maybe something a little more tender. It blossoms whatever it is, and maybe this is the wrong time to daydream just so slightly about the future, but it makes him realize that even with how new and fresh his feelings are, Shirayuki is the woman that could stand by his side, if he ever told her how he felt.
Yet, his title's always gotten in the way, and despite that, he feels as if she could handle the title, just as she stands before him, cheerful, ready to head off to work, determined to do her job well, a job that she's worked hard for, one that she loves.
And maybe a woman is not normally grown into a princess through herbalism, as many royalty would loudly protest to getting their hands dirty, watching life sprout up, but Zen sees something here in her that it's hard to find words for. Just, he knows that he should quell his hope, especially since he doesn't want her to follow through with his confession for the sake of his title, something vaguely similar to what almost happened, when Shirayuki found no other way to save Zen from poison than to submit to being Prince Raji's concubine.
Zen rightly knows that Shirayuki probably should feel done with princes and their interest in her, and he doesn't want to impose. It wouldn't be right on her, and yet, he knows that one day he'll be honest with her, and tell Shirayuki exactly how he feels and hope that she doesn't think of his title as she looks up at him.
That title of his has been self-taught to stay on his mind, and right now, he sees a woman standing before him that is probably more worthy of his title than he has ever been. She stands strong and confident, and though she's not about to head off to royal duties as she is an herbalist, not a princess, he still sees that drive that makes nobility flourish.
It's a level of clarity, of the depth of his feelings, of the depth of her character, that Zen doesn't feel ready for, as he shifts back into the normalcy of their friendship, feelings tucked gingerly under wraps once more. Awe threatening to burst out of his chest as he looks at her, and he knows that one day these feelings might grow into something too big to contain, though he'd work to tuck them inside and hide them, if that is what she wants him to do.
Ultimately, Zen never wants to force his title on anyone, because already it feels stifling enough for him, and he was born into it. So, Shirayuki will one day tell him whether there is reason for the hope in his chest or whether her permanence is a friendship only made stronger, despite it's rather unusual beginnings.