>>25522937One one hand lmao that’s a genuinely funny response
On the other, as an actual plot point, it might be an illness that legitimately couldn’t possibly be cured, probably some rare genetic disorder, or it happens that managing to use a cure could be an extensive and advanced process that might give away her time traveler status, and in some manner risk her being exposed to danger, losing her powers, or losing you.
There’s also the question of how far her time travel powers in-universe go, and whether she could even get together the sort of resources to make it happen, and then manage to convince someone to go through with treatment from some girl they've only just met for a disease they’ve never noticed symptoms of.
If I were to write this, I’d either consider having her address the issue and have part of the tragedy be her downward spiral as her attempts to save Anon always fail, have the cause of death be something different (maybe just a curse or something, causing various horrific accidents after a certain date until you die), or maybe even have her be unwilling to cure you because you always end up leaving her at some point or
another or simply fail to hook up with her in timelines where you survive.
>>25520737This.
After enough loops, she’d probably have made a slip up or two that you’d learn about, and I can only assume would know your knowledge of her abilities is another thing she can always undo, which would mean a few journal entries mentioning you “finding out” and a reset back by a short time to prevent it. But even if you tried your best, once you’re in the ground, you can’t really do anything to stop her, and for people who live by the assumption that what other people don’t know won’t hurt them, lying to keep someone they know happy before they die (as she’s done in the story by that point) would seem perfectly natural. Maybe even easy.
>You have a conversation with her over the journal, causing her to break down into tears as she admits she’s been abusing her time powers to stay with you for decades>you tell her how beautiful she is, how much you love her, and how much you appreciate that she’d love you so much>but she needs to move on, one day, and accept your fate>she tearfully agrees, and you spend the last days you have together, living your life to the fullest, even getting to see some of the funny tricks she can do with time travel since you know now>but these days come to an end all the same>on your deathbed, you faintly hear her apologizing to you, which you assume is for not saving you and hiding what was going on>you hold her hand, and tell her she’s done all she needed to, and never to forget how beautiful she is>she only continues, even as you lose consciousness for the last time, content, thinking you’ve lived your life well enough for both of you to be satisfied, and that she’ll eventually be at peace> you never foresee her an hour later, standing outside your room, quietly apologizing for lying to you again as she pulls out a glowing golden pocket watch, and starts rewinding the hands one more time 
