100 Prompt Challenge - Astelle

Prompt 7: A very long time ago, I remember reading an Astelle oneshot on A03, where Asta and Noelle each have some misunderstanding that they're a couple and start acting the part. I wanted to do something similar, though much shorter obviously because I'm studying for an exam. 

—

Asta blinked at the flower in his hands.

A deep blue hydrangea, petals soft and delicate, wrapped in a thin white ribbon. Noelle stood before him, arms crossed, foot tapping against the dirt. Her cheeks were red, though whether from embarrassment or the cold, he couldn't tell.

"Well?" she asked, impatient as ever. "Are you just going to stare at it all day?"

Asta swallowed.

He knew this flower.

Not from books or fancy noble gatherings, but from home—Hage Village, where traditions weren't just customs, but unspoken rules. Blue hydrangeas were rare, said to bloom only in places where the soil was rich and the air was kind. That's why, for generations, they'd come to symbolize lasting love, unwavering devotion—engagement.

Sister Lily had told them the story once. How, long ago, a farmer too poor to afford a ring had offered his beloved a blue hydrangea instead. A promise. A vow. Ever since, it had been the quiet way of asking someone to be yours.

And Noelle… had just given him one.

Asta's grip tightened around the stem. His pulse roared in his ears. Had he—? Had she—?

Noelle huffed, arms tightening around herself. "It's just a stupid flower," she muttered. "Don't overthink it. I just—I wanted to thank you, okay? For everything. So… don't make a big deal out of it."

Her words should have been enough to ease his panic. They didn't. Because despite the casual tone, she looked… happy. Genuinely happy. A small, rare smile tugged at the corner of her lips, something warm and unguarded. She was proud of this. Of giving it to him.

And that? That was dangerous.

He should tell her. Should clear up the misunderstanding before it spiraled.

But the thought of wiping that look off her face felt like a crime.

So he swallowed the truth, forced a grin, and nodded. "Thanks, Noelle. I love it."

She looked away, ears turning red. "Obviously."

—

Asta didn't mean to change anything. He really didn't.

But after receiving that, he couldn't just act the same way. Noelle had—however unknowingly—claimed him.

So he started treating her like she had.

He carried her bag after missions. Handed her snacks whenever she looked tired. He threw casual "You look cute today" comments like they were as normal as breathing.

Once, she'd fallen asleep on the couch after training. He'd draped a blanket over her, then—on impulse—brushed a strand of hair behind her ear.

She had almost caught him that time.

Almost.

She never told him to stop.

And that? That made it worse.

—

Noelle didn't know when it happened.

One day, Asta was the same loud, annoying idiot she'd always known. The next, he was… different.

Not in any big way. He still trained at ungodly hours. Still yelled about surpassing his limits. Still made a fool of himself at every possible opportunity.

But then there were the other things. The way he lingered beside her after missions. The way his compliments came too easily, like they were natural, second nature. The way his hand brushed against hers, only for him to not pull away.

And the worst part? The absolute worst part?

She liked it.

Which meant she was in trouble.

Because it wasn't just Asta acting strange—she was.

The first time he offhandedly said, "That color suits you, Noelle," she had spent a full five minutes staring at her reflection in a store window, trying to figure out if he meant it.

When he casually grabbed her wrist to pull her out of the way of one of Luck's stray attacks, she had spent an entire mission hyper-aware of where he was standing.

And then there was the worst incident of all.

They were at the market. Nothing special. Asta had dragged her along under the excuse of "helping him pick something out."

It wasn't until later—too late—that she realized what he had been looking for.

A necklace. Silver, with a single small blue gemstone in the center.

She had stared. Long enough for him to notice. Long enough for him to say, "You like it? Here, it's yours."

And before she could even think to refuse, he had bought it and put it on her himself.

Like it was normal.

Like it meant nothing.

She had barely been able to breathe.

And that was when it hit her.

She didn't know who started it. Didn't know if it was her giving him that flower, or him suddenly acting like her boyfriend, but somewhere along the way—they had started dating.

And neither of them had actually said anything.

—

The realization came crashing down when Sister Lily smiled at her during a visit to Hage.

"That's a lovely hydrangea," she had said. "Asta must be overjoyed."

Noelle blinked. "Excuse me?"

Sister Lily gave her a kind look. "You know. The tradition. It's a very special flower in our village."

Something in Noelle's chest froze.

"...What kind of tradition?" she asked, voice dangerously even.

Sister Lily laughed, oblivious. "Oh, dear. Did he not tell you? A blue hydrangea is a proposal gift. It means you're already engaged."

The world stopped.

Her heart stopped.

Everything stopped.

She turned, slowly, to Asta, who was standing right beside her.

"...Asta."

He flinched.

"You knew?"

He rubbed the back of his head, sheepish. "Uh… yeah?"

Her fists clenched. "And you didn't think to tell me?!"

"I mean, I thought you knew!" he defended. "And you were so happy, and I—I didn't wanna ruin it!"

"Ruin it? RUIN IT? You—YOU IDIOT!"

She shoved him. He barely stumbled, grinning nervously.

"But, uh, you know…" He glanced at her, eyes softer now. "I wouldn't mind if it was real."

She froze.

He smiled. "I mean, we kinda already act like a couple, right? Might as well just make it official."

Noelle turned away, crossing her arms to hide the heat rising to her face.

"...Fine."

A beat.

Then—Asta grinned. "Wait, really?"

"SHUT UP BEFORE I CHANGE MY MIND!"

He laughed. Loud, bright, happy.

And despite herself, despite the absolute disaster of a misunderstanding that led them here—

Noelle smiled too.