Despite not knowing who the girl was in his dream, he felt that she was the only one who could ever move his heart and feel love again. And that was why he was willing to sacrifice anything just to be with her again.
The emotions of love that he had felt in his dream when he was with her were too vivid, so he understood that it wasn't fake. There might be something that he had missed in his dream and he was willing to find out what it was. It might be the key to meeting with her again.
"Asther, I just remembered that I had a dream with a girl and she is my lover in that dream."
When Asther heard that from Allen, he can't help but cringe at Allen's dream.
'Is brother sexually frustrated? Is he yearning for having a lover? Sigh, even I can't invent a lover for him.'