"No. It can't end this way. It's not right." Her voice was tiny, barely audible to Elsa over the ringing in her ears.
"It had to be this way, Anna." She tries to smile, but can't find the energy. She settles for speaking, knowing that these words, on the frozen sea, her dying words, are both the first real words they've spoken to each other and years, and the last. "I thought you were frozen. I thought that I...that I had..." She breaks off with a deep cough, tasting blood in her mouth. It's an unpleasant taste, metallic and bitter. Anna smiles, a broken smile full of pain and heartbreak.
"No, it didn't! I tried to save you, I tried to stop him, but I couldn't make it in time! I should have been faster, I should have never trusted him in the first place, Elsa, I'm sorry, you were so right..." Each sentence is punctuated by a stifled sob.
"It's okay, Anna. You're here now. We're together, for now." Elsa can feel the warm ache in her chest subsiding into deep icy cold, spreading throughout her body. The sensation is unfamiliar and unwelcome, the Ice Queen thinks. She shouldn't have even been able to feel the cold. She knew it was time. There would be no other chance to say it. "I…I just need to tell you, you need to know. Anna, I love you." There. The words were out.
Anna smiled, looking down at Elsa, resting her head weakly in her lap. The ice in her heart was spreading now; she couldn't feel her legs or her arms. But she had no desire to move, no intention of leaving her sister in what was most definitely their final moment.
"I love you too, Elsa." The words were clear and firm, as if she was surer of that than anything else in the world.
Elsa reached her hand out to touch Anna, to stroke her face, make sure she was real. She gave a weak cough, spasms wracking her body.
"Just thought you…needed…to know." As she breathed her last, she could feel Anna growing colder, the last remnant of the magic she had used against her in a furious fit. She could see the world growing dimmer, Anna growing colder, the ice traveling up her body, encircling her face, turning those delicate features into eternal ice, as Elsa slipped into eternal sleep.