[There are so many things he wants to say. He understands the pain of loss of losing everything over and over. In part, that's why he's here fighting her on this. He doesn't want to lose anything anymore.
But what Saya is referring to is something he can't grasp or understand. Life, for Zero, at least in the last five years, has been something extremely limited and even considered inevitable in the short term. Due to his situation, another year was an unexpected blessing.
Since completing the fragmentation of the twin curse and ingesting the amount of pureblood that he has, the span of his life was just a number of question marks, only to be answered once it was all said and done. There could be the rare hunter, such as Kaien Kurosu, who had the rare side effect of longevity of life--having stopped aging over two hundred and fifty years ago.
Even that was a drop in the bucket to a being that could live forever.]
I can't say I understand. At least not completely. I've lost so much...that I understand just wanting to give up and find peace. But...I just don't want to lose anything else anymore either.
[He exhales tiredly, frowning as for the hundredth time he finds himself without the words or the ability to get his point across in the way that he feels he should. Thinking for almost as many times that Yuuki was much better at this sort of thing than he was...]
I promise I'll do whatever you guys decide...as long as you discuss this with Yuuki first.
This is her specialty. She's promised to kill people in this sort of situation, who wouldn't die otherwise.
But at the same time, if I'm understanding correctly...you're the only one here who could stay by her side for eternity--otherwise she'll really lose everyone.
[Putting her in the exact position you're trying to escape from.]