Zimmerman (1982:80) – Entschlossenheit - Schuld - Sein zum Tode

As resolute, Dasein   discloses its ontological finitude (guilt). But for such resoluteness to be fully authentic, Dasein must disclose itself in terms of its most unique and individuating possibility: Being-towards-death. Anticipation of death reveals the mortality at the heart of ontological guilt. Resoluteness, the disclosure of Dasein’s own finitude, becomes fully authentic when it anticipates Dasein’s death. In anticipatory resoluteness, Dasein gathers itself into a unified whole. Dasein becomes fully resolute only because it anticipates its own end. The existential possibility of anticipating my death, however, requires the existentiell act of resolving to actualize it. Let me explain this in less Heideggerean language.

Any time I make a specific resolution, for example, to marry someone, I choose to actualize certain possibilities and to let others go. Resoluteness presupposes some recognition that I am limited. The more steadfast I am in my resolve, the more I understand my finitude. The practice of resolving leads to deeper individuation. Becoming more aware of my mortality, I become more aware of my individuality. Anticipating death is possible for me because I always have some self-understanding. My theoretical knowledge about my mortality becomes concrete, however, only when I make a specific life-decision: when I choose to go this way, not   that way. Decision makes me more aware of my mortality, and awareness of my mortality makes me more resolved to be who I am: a mortal being trying to be who he already is. (1982, p. 80)

[ZIMMERMAN  , M. E. Eclipse of the Self. Athens: Ohio University Press, 1982]