Harsher in Hindsight: Reinforce assures Hayate that she's content with her sacrifice, calling herself "the happiest magical tome in the world". However, Strikers Sound Stage 03 reveals a message she leaves behind for Reinforce Zwei, in which she admits that she wishes she could live together with Hayate and the others in their future life.
Reinforce tells Nanoha that she'll understand her reasons someday, when she too has someone she "loves more deeply than the sea", and wants to protect above all else. By the end of StrikerS, Nanoha will indeed learn what that means.
Reinforce's last request to Hayate is that she pass her name along to "the next vessel which will hold her magic". The events of Strikers Sound Stage 03 strongly imply Reinforce knows full well that Reinforce Zwei will be born someday.
