Hi again! <3
Ah well, she honestly doesn't know haha! She can never really be sure and she is given no assurance that what she is doing is the best option. All she knows is that she has to "set things right". (Lol, the MC is more an MC who thinks with her heart actually than with her mind).
I'm actually going to make a sort of prequel for this game which kind of sheds more context into their situation, but here is a teeny tiny spoiler for context into her reasoning:
------------------------SPOILER SPOILER SPOILER--------------------------------------
Her beloved is a actually a very influential game developer, like Toby Fox levels of influence. In their original timeline, he would go on to inspire millions and millions of people around the world! Probably even a whole generation of players was influenced by the game! Even she herself is a huge fan of him! And well, she sees all these lives changed and influenced by the game. She sees how happy he is and the community that has been built upon his and his team's creation, and she...just can't bear to take that away from him. She sees how he shines, more so when he sees how much of an impact he has made on others. So for her to see him deviate from that path, she slowly panics. Within their relationship, she tries to set him up with his friends and the connections he had built before, but again he comes back to her. She does think that maybe it's fine that she has that relationship with him, but her time travel experiences have made her obsessed with stability, and she knows that the upcoming choice she makes would be a make or break moment. (This too would be explained in the prequel, but more so the sequel). So, she gives in and chooses the safest path, the one she is sure he shines the best. After all, with her beloved, she cannot take any chances on his future (her time-loops are limited to a certain timeframe after all, so she may not get the chance to undo her decisions).
She can't tell him because she's honestly not ready yet. Prior experience has taught her the perils of letting others know of her situation, and although her heart tells her she can trust him...well her mind simply isn't ready yet, but unfortunately, she has to make a choice.
I hope this cleared up some things! I do wish I could have added more in-game context, but again, jam rules!
Thanks again for your thoughts!
(I forgot to add, but this is also an interesting take on it! It's actually a lot closer to the view of the LI! And this view of yours will actually be sort of explored more in the sequel! More so as the results of her choice is actually directly seen in the sequel).