Liesl comments on the idea of being "twice-born" in chapter five of Robertson Davies' Fifth Business. Here, Liesl is telling Ramsey to really change his life. They are speaking about Calvinism and Christianity, and Liesl suggests that Dunstan is not making the most of his new life.
The concept of "twice-born" refers to both Dunstan's name change and "new life." That said, Liesl does not believe that Dunstan is really changing how his life could be. Instead, she suggests that he is living with "the revenge of the unlived life." She is relatively disappointed that even with his recent "birth," Dunstan is nearer to death than birth. Therefore, her comments on being "twice-born" are relatively negative (give she fails to see any success in Dunstan's new life (or second birth).