General Ferdinand Foch believed that Germany needed to be permanently weakened, and that the treaty of Versailles didn't do nearly enough. In 1919 he said

This is not peace. It is an armistice for 20 years

This would indicate that some, at least, believed that another war was inevitable.

Ruth Henig, Versailles and After, 1919-33(Routledge, 1995), p. 52.

A related question: I have recently gained a huge interest in the history of Europe in the first half of the 20th century. Especially the pre-wwi period and the history leading up to the war. Can anyone recommend any history books on the subject?

Thank you in advance.

It will take you a great deal of time, but read Zara Steiner's "The Lights that Failed" and "The Triumph of the Dark." These two behemoths effectively answer your question with a resounding "No." Steiner argues that until internationalism really started to break down and crumble, there was actually a good deal of hope that there would be no war at all after the First.

Essentially, while the post-war settlement was acknowledged as imperfect by all parties, there was a great deal of optimism that not only would the peace hold but that a new age had dawned.

These two books by Steiner, or "Zara's version" as John Ferris has described them, are the end product of gathering effectively all the current histories, analysing them, listening to experts in different areas, and compiling the result. (Professor Ferris has argued that these two books will be the foundational works on the inter-war period for the next fifty years).