A paternalistic or maternalistic government may influence some people to believe certain Tory/Whig*1 political positions, as opposed to those of the disloyal opposition. But more often it's a charismatic leader, like Hitler, who preaches a Big Lie*2 as "our truth", which is intentionally distinguished from the beliefs of despised Others (them). For example, Donald Trump convinced a surprising number of his adoring followers (fans -- fanatics) that the science-supported COVID vaccine was ineffective, and besides, the virus itself was a liberal hoax. Based on their trust in Der Fuhrer, some even ingested bleach or ivermectin (horse dewormer). The current issue of Skeptical Inquirer magazine (Vol 47, issue3) mentions the vaccine & mask beliefs, among many others, under the title : "Who Believes Unsubstantiated Claims?".
That magazine is devoted to the question you asked. Although its position on a variety of issues is primarily characterized as Science vs Pseudoscience, its philosophical approach is simply independent thinking as opposed to going along with a crowd. All too many of us, are dependent believers, who look to someone else to sanction (approve) their beliefs. Not just any "alter ego", but someone in a position of authority in their personal Clique (in-crowd, fellowship, club). Religions and political parties are major players in the dissemination of acceptable beliefs for members of a particular faith society. That social group may be a mainstream religion, or an underdog religion, or a racial category, or economic interest class, or merely a self-interest group, such as the followers of internet conspiracy theorists like Q-Anon. To be an independent believer though, usually requires the courage & self-confidence to go-it-alone.
Apparently, most of those Tribal or Herd believers are uncertain of their own ability to discern the truth in a crazy mixed-up world. So, they place their trust in someone who seems, or claims, to have their personal or tribal interest*4 at heart. Unfortunately, that oft-misplaced trust in substitute parental figures may result in childishly unsophisticated black-white beliefs, and Us-vs-Them antagonisms. So, if the OP indicates a lack of confidence in personal fact-finding ability, then there are two options : A> find someone else with the confidence you lack (teacher, master, con-man), or B> take responsibility to educate yourself in the science of knowing : Philosophy.
In these days of Alternative Facts*3, though, even philosophical loners need all the help they can get. But there is no easy way to distinguish gullible ego-stroking Alt-truths*4 from skeptical superego discernment. So, the first, and hardest, step on the road to Wisdom, may be to off-set your own limitations, pump-up your courage, and gird-up your loins for the long & winding road toward the ideal of pure mountaintop Truth. "What is Truth?" That depends on how you, or your clique, defines the foundation of Belief.
PS__Another long-running magazine, funded by subscriptions not advertising, is SKEPTIC. Besides giving many examples of what not to believe, these publications teach readers both scientific facts and philosophical methods for "choosing what to believe".
*1. Whig vs Tory :
Whig and Tory, members of two opposing political parties or factions in England, particularly during the 18th century. https://www.britannica.com/topic/Whig-Party-England
Simplistically : Whigs = pro-aristocracy ; Lords ; top-down government --- Tory = anti-monarchy ; Commoners ; bottom-up government.
21st century America : Whig = Republicans, religious & political conservatives ; Tory = Democrats, religious & political liberals
*2. Big Lie :
A “big lie” is an extreme distortion of the truth, used for the purpose of spreading propaganda. It is often somewhat outrageous.
In theory, people will more easily believe a big lie than a smaller one, because most people assume that there is evidence to support any statement of great magnitude.
The term was coined by Adolph Hitler in his autobiography, Mein Kampf.
https://politicaldictionary.com/words/big-lie/
*3. Alternative Facts :
"Alternative facts" was a phrase used by U.S. Counselor to the President, Kellyanne Conway, during a Meet the Press interview on January 22, 2017, in which she defended White House Press Secretary Sean Spicer's false statement about the attendance numbers of Donald Trump's inauguration as President of the United States. When pressed during the interview with Chuck Todd to explain why Spicer would "utter a provable falsehood", Conway stated that Spicer was giving "alternative facts". Todd responded, "Look, alternative facts are not facts. They're falsehoods."
https://en.wikipedia.org/wiki/Alternative_facts
*4. Tribal Trust :
Referring to affiliation (hence trust & loyalty) with a group; interrelated by genetics, or politics, or religion, or simply self-interest.