Germany was 1/3 Catholic, and the Catholics were uneasy with his views until this happened.
Reichskonkordat
The Reichskonkordat ("Concordat between the Holy See and the German Reich"[1]) is a treaty negotiated between the Vatican and the emergent Nazi Germany. It was signed on 20 July 1933 by Cardinal Secretary of State Eugenio Pacelli, who later became Pope Pius XII, on behalf of Pope Pius XI and Vice Chancellor Franz von Papen on behalf of President Paul von Hindenburg and the German government. It was ratified 10 September 1933 and it has been in force from that date onward. The treaty guarantees the rights of the Roman Catholic Church in Germany. Whenbishops take office Article 16 states they are required to take an oath of loyalty to the Governor or President of the German Reich established according to the constitution.
https://en.wikipedia.org/wiki/Reichskonkordat
After that, Hitler won with 99% of the vote.