1 Throughout the series there are many mentions about the next life. ML is emphatic about this belief and talks about it several times to MJH. They had a happy time, both were able to mutually prove their love. It is not entirely clear whether she actually died in that chair. And let's not forget that MJH was also poisoned. He had promised to find the flower when the snow returned and the snow returns in this scene. What would be the point of making a scene with snow, an event exclusively related to the flower?
2 The plot has a strong symbol, the undying flower, whose meaning is that they would not die before fulfilling their revenge.
The plot is also focused on rebirth, the opening song talks about rebirth. The scene that follows the falling snow is of a stunning sunny day in Qingzhou. We see everyone who died there, alive. It's not a dream of his, the type of image doesn't indicate that it's an oneiric experience, nor a memory, especially because they didn't know each other before the fire. It's a scene of rebirth.
3 MJH's arrival indicates that he is also experiencing his rebirth and, according to promise, doomed to the fate of living another life with ML. This final scene indicates that their story begins again in a different way, suggesting that they will have a happy life, free from the mistakes of that previous life.
4 Western films and series recurrently have happy endings, it's almost a pattern, this is related to our history. But Asia has a history of more than 5,000 years, it is rooted in philosophy, in the mystic of death in a profound way, it leads us to a permanent exercise of interpretation, because the series, even the most basic ones, bring this baggage, in a special way, cdramas commonly end their series without ending... without the conclusive cliché pattern so present in the West.
5 I repeat: MJH's arrival indicates that he is also experiencing his rebirth and, according to promise, doomed to the fate of living another life with ML. Believe me, at this time, MJH and ML are picking undying flowers... There is no longer any fear of dying...
