"He will love the book!"
Translation:Han kommer att älska boken!
Think of "ska" as the English "shall" (except in more common usage). "Shall" implies the mandatory. Here, you probably wouldn't say "he shall love the book" (han ska älska boken) because that implies a level of certainty that you probably don't have. "He's going to love it" or "he will love it" both imply "I strongly suspect this is something he will enjoy but I can't guarantee it." So: "han kommer att älska boken."