Why I chose "I'll live for you until the day we'll meet again"?
Because this is the positive conclusion of the series and I wanted to explain Shion's feelings.
The title is a bit long >.>" but I think that it's perfect for them.
The day that he knew that he could disappear, he asked to Shion to take care of his little sister Satoko, and to be for her the falling star.
In Meakashi-hen Shion
became totally mad because of Satoshi's desappearance and she kills Satoko, thinking of her as his assassin.
But in the next arcs she's different and she takes care of her as a sister. Their relation becomes close and Satoko calls her "nee-nee", as the way she called his brother "nii-nii", because of her love for him.
Satoko-chan considers them as a couple and Shion as a daughter-in-law. So, one day surely Satoshi will awake from the coma and Shion and him will be happy together!
She'll wait for him but I'm sure that that day will come!