I understand that Misha cannot fully trust Rei right away, as she is not the same person as before. But right now, she is just being difficult. Actions speak louder than words. Forget how her foresight saved ya, won't ya? She is trying to help the person you love, and you weren't initially planning to life a finger. I wonder, who would benefit from the plan being successful? Misha, as Yu is freed from her engagement and both can pursue whatever relations you want.
And tbh, I think they mishandled Misha's character so bad. She is Rei's best friend, but her screentime probably can't even beat Rod in terms of actual story development. I had never seen a best friend with so little involvement in her best friend's life. I mean, the time they spend together, it is because they are in the same room and they are in the same circle of friends. Her role of best friend really didn't come through to me.