Practice with diction. The end can be interpreted in several ways.
Robin's eyes were always blue. Sometimes they were the indigo blues of deep waters crashing down on top of each other, and other times they were as clear as a tidepool with a thousand miniscule flickers darting back and forth in the light. The blues sometimes changed to the melancholy purple of a quiet, chilly dusk, just relishing the solitary silence of a hot cup of coffee. In the morning, they were the pale blue of a fox wiggling its way out of a snow drift, and then they cleared up later on midday, alert as a wolf, blue as the cerulean dolphins that leapt and played alongside the ship.
But lately, Robin's eyes were an empty blue, a vanishing blue that sometimes seemed like it wasn't even there anymore. It was the vanishing blue of the whales that silently eyed the ship before drifting away into the endless waters.
"There's no need to worry. I'll be fine."
Franky held onto her hand as long as he could, closing his eyes and feeling her slender fingers running through his calloused, artificial palms. Then her hand began to slowly slip away like how the stars stole away to make way for the dawn.
Franky didn't want to see the dawn.
"No... I'm sorry. I can't quite recall..."
That empty blue began to occupy her sorrowful eyes that held so much pain and memories behind the smile and mischief. It was the empty blue that told Franky that things were no longer the same.
"I love you... Franky, I..."
Chopper couldn't do anything. Nothing helped. No medicine, therapy, psychological analysis, scrapbooks, nothing.
Robin's memories were slowly slipping through their fingers.
And so Franky held onto that fading blue that was her eyes, painstakingly retelling all of their adventures in a hope that the sparkling cerulean would return. It wasn't just him, either. Everyone tried their best.
"Onee-san, remember that time we all fought against that splithead and we lost you for a second, but then everything turned out okay? Everything turned out okay..."
"Sogeking forgave you for what you had done on the Sea Train... after all, you are one of our nakama... but... sorry, Sogeking c-can't be here in person..."
"I didn't know who you were, so I was a bit suspicious. I mean, I wasn't suspicious! And... I didn't mean it when I called you an octopus...!"
"Robin-chan, you told us that you would die gladly... like we would ever let that happen... we would never let you leave..."
"Remember you and Franky-san were the first to listen to my tale? Laboon... and then that phenomenal battle with Oz... you were incredible, Miss Robin..."
"You were always in the shadow of suspicion. But you proved yourself. You... will always be one of our nakama, Robin..."
"Robin. You said you wanted to live, right? So live, live for all our- no, your sake..."
"Robin..."
Life went on. The stars disappeared from the violet-smudged sky, and the sun broke its way through. Franky's heart was never the same again.
The dawn had arrived.