Q: I purchased The Fault in Our Stars on my iphone but it wont sync to my ipad and does'nt show up in itunes.

Movie are not part of the automatic downloads feature in Settings> iTunes & App Store>Automatic Downloads. Only apps, songs and books will download across devices if you have the feature enabled.

Depending upon where you live, not all movies can be downloaded again for free. if you download all of your content in iTunes on your computer and then sync it to the iPad, you don't have to worry about things like this because your purchases are always available in your iTunes library. If you want to go PC free and rely on iCloud only, there are sacrifices to be made.

Perhaps, you do not fall into this category any and it is some thing else going on, but you can look here to see what I am talking about.

iTunes in the Cloud, iTunes Match, and iTunes Radio availability

IF you do sync with iTunes, transfer the movies from the phone to your computer and then sync it to the iPad.

iTunes Store: Transfer purchases from your iOS device or iPod to a computer