1)
Why does the Torah write here "be'Seifer ha'Torah ha'Zos" and below 29:20, "be'Seifer ha'Torah ha'Zeh"?
1.
Rashi (in 29:30): Because since here, the 'Tipcha' is underneath the word "be'Seifer", separating it from "ha'Torah", "ha'Zos" refers to "ha'Torah" (feminine) - 'the book of this Torah'. Whereas in the Pasuk later, since the 'Tipcha' is underneath the word "ha'Torah" "ha'Zeh" is connected to "be'Seifer" (masculine) - 'this book of Torah'.
2)
What is the meaning of "Ya'alem Hashem"?
1.
Rashi: It means that Hashem will bring them [upon you].
