Evelyn writes a letter to Rave saying "It is so strange to be a whole world away from you." But when Rave is burning all her letters she wrote to him it said "It is so strange to be so far from you."
It is possible that it was a different letter that we see burning. It doesn't seem very logical why they would show to different letters with almost the same phrase on them, but hey! It's a possibility.
Plus, why would they go through the trouble of actually writing out the same letter she wrote to him before, and get it wrong? When I'm away from the one I love, I say things like "I miss you" and other little things like that ("It's so strange being so far away from you") over and over again, in different e-mails/letters, so it's not totally improbable that it was meant to be a different letter.
But then again, why would they do that? .. and yet again, why were you reading the letter in the fire anyway? I didn't even notice that..