Stalin's fears were based on several factors. First, he knew that the majority of people in Eastern Europe were not enthusiastic about communism. Many had been forcibly incorporated into the Soviet Union after World War II, and they resented the loss of their independence. Second, Stalin was aware of the growing popularity of democratic movements in Eastern Europe. These movements were inspired by the success of the Marshall Plan in Western Europe, which had helped to rebuild the region's economy and promote democratic values.
Third, Stalin was concerned about the potential for nationalism to undermine communist control in Eastern Europe. He knew that many people in the region were proud of their national identities, and he feared that they might use free elections to express their desire for independence.
In order to prevent these threats, Stalin took several steps to suppress dissent and control political activity in Eastern Europe. He installed communist governments in each of the countries in the region, and he made sure that these governments were loyal to him. He also created a network of secret police forces to monitor and suppress any potential opposition.
As a result of Stalin's policies, free elections were never held in Eastern Europe during the Cold War. The region remained under communist control until the collapse of the Soviet Union in 1991.