The Fault in Our Stars font here refers to the font used in the cover of The Fault in Our Stars, which is a novel by John Green and it tells the story of a sixteen-year-old cancer patient who is forced by her parents to attend a support group where she meets and fall in love with an ex-basketball player and amputee. A feature film adaptation of the novel was released in June, 2014.
The title in both the book cover and film poster features casual chalk style lettering, which is probably custom designed and not a font. But there are some fonts you can try to create a similar feel, such as DS Eraser (free), Frank Reaction, Drawzing.
Download The Fault in Our Stars Font
We are currently unable to find a free alternative or a font similar to the commercial font identified above, and you will need to follow the relevant links above and purchase the font.