The theme of The Fault in Our Stars is that with love you can make it through the difficulties in your life. Hazel and Augustus both have cancer and could die any day, yet they still love each other and help each other through their difficulties. No matter what would happen between them they would still be there for them. You see this in the book when Hazel is sick Augustus doesn't care, he still loves her and does not give up on their relationship, because he knows that their love is worth it.