@erraticoptimism from here
It's a good while before it makes sense.
Graced with the responsibility of looking after his brother's belongings, he as all younger brothers are wont to do set to rifling through them curiously and amongst the them was a single earring in a fabric pouch. It doesn't make sense. Ace doesn't have piercings, let alone something like this so Luffy takes it out and sets it aside to ask about later. The thing about 'later' though is it's after a stretch of time and in that time a lot can happen. A lot does happen. It's not even momentous, just enough that the jewelry slips his mind and once it's no longer in his brother's things the fabric pouch becomes just another object laying about that his fleeting attention span never really latches on to.
Not until he sees its counterpart. Then it clicks, the memory bubbling to the surface and he can see it plain as day in his hands, recalls the weight of it and the confusion it had elicited. It's days later when he finds it again, pouch twirled 'pon his finger as he walks until he can drop it into her palm. "I think this is yours! Isn't it?" There's a story and he's dying to hear it. He's missed a lot in the years he waited 'til he could hit the open seas like his brother.
Due to the nature of their professions it wasn’t unusual for her and Ace to go long periods without seeing each-other. Her and Buggy and Cavendish were the same way. Just part of a pirate’s life to be separated from friends sometimes.
She hadn’t fussed too much when one of her earrings went missing after her last little rendezvous with the Firefist, she knew it would turn up eventually. She kinda liked the one earing look anyway!
“We aren’t here on business! It’s a break! So you lot relax and don’t get into trouble! And don’t let Elaine run amok when you have her!”
“Don’t worry Martha! I’ll look after her!” The young navigator grinned and bounced on the balls of their feet, carrying the toddler on their hip as they and the other crew members split off to enjoy their time goofing off.
______
That had been a couple days before. The crew was enjoying their break and Martha was just people watching---though a young kid, looked to be around her navigators age? Was heading right for her, twirling something around his finger.
She blinked at Luffy, utterly baffled, as he dropped the pouch into her hands.
“Huh...?” Looking down at it, she opened it and stared at what she saw. “My earring!”
Her gaze returned to Luffy with a chuckle. “Yeah, this is mine; but I don’t think we’ve ever met before kid. How in the world did you get this?” She inspected the bronze hoop for any damage but found none that wasn’t there before, putting it back in her ear with a smile.