DISCLAIMER: Marvel characters are not mine, or Clintasha would be so canon there'd be no need to write fanfiction.
Natasha Romanoff didn't wear her heart on her sleeve. Or her neck for that matter. She knew that it was dangerous; any personal items could be used as leverage and be held against her in ways that were more painful than any kind of physical torture could ever be.
She knew that and she wasn't the reckless type. She never had been. The job had always come first, even before SHIELD.
But once part of that agency a lot of things had changed. She began to work, to use her skill set towards something good, even if sometimes she couldn't help but question what that was.
She made herself very aware of everything she had done and, being with the good guys, she tried to right her wrongs.
She was given the chance to choose who she wanted to be. It wasn't an easy process, but she was never alone. Clint Barton was the man who gave her that choice, and with it (though she'd never say it), he became her savior.
He then became an ally inside a faceless agency of people who didn't trust her and she equally didn't trust. He was the first one on her side, being the one who brought her in. Warming up to Fury (and the other way around) had been a process that had taken years and now she considered the man as her mentor.
Clint Barton had changed a lot in her life, that was for sure. He had given her something nobody else had. He had become her partner.
First it was missions they shared. They worked well together and even if they would never admit it, they had fun. She trusted him in the field, until one day she realized she trusted him outside the field as well. That's when he became her friend, and as much to her surprise, that trust and friendship was a two way street. That had all been years ago, and from there, their relationship only grew.
Somewhere along the way she realized her feelings for Clint run much deeper than she cared to admit. There was a line that neither of them would cross, drawn from years and years of partnership and friendship, when they both realized they couldn't afford to lose each other.
Some years ago, a different kind of tension started to build. Clint knew that he was in love with Natasha. He was mesmerized by the sole sight of her and he loved her more and more every day. But he also knew that what they had had taken years to build and that trusting people didn't come easy for Nat. He wasn't about to ruin that by telling how he truly felt, not as long as she was securely a part of his life.
Natasha knew her feelings for her partner had shifted some time ago but she didn't dare put a name to it. (Deep down, Nat knew it was love but she was too afraid to admit it).
But after the Battle of New York, everything had changed. She had only reacted when Coulson mentioned her partner was in danger, and the pit of her stomach hadn't eased until he was safely next to her, back to being himself. She had been too afraid of losing him. Funny, because in all of their years as partners, they'd become close to losing each other more than enough times. It was an occupational hazard. Except this time, when Loki had taken over his mind, she was afraid of losing him to himself.
It was unknown, that danger, whatever was happening t Clint. That had scared her the most.
They had fought before, training, a million times, but he had fought her like he didn't know who she was and what she meant to him, like she was the enemy. And that thought alone was the single scariest thing she had experienced in years.
The world around them had changed. It wasn't spies and soldiers and missions anymore. There were Gods and magic and too many unknown variables neither of them could control. So she decided to take control of the few things she could. She needed to.
After the Battle, after the dust had settled, she realized her heart wasn't hers anymore, so she fully gave it to the man who owned it, the one who had been next to her all along.
When Clint Barton went on his last SHIELD mission before the Hydra outburst, they had been together in secret for some time. And they loved each other.
So when he gave her that silver arrow necklace to remind her of him, for the first time in her life, Natasha Romanoff was ready (and proud) to wear her hear on her neck…