We know what we value most highly only by testing. At a time when the bishops (or many of them) have shut the Church down, some Catholics have discovered that they value the Sacrament so highly that they are prepared to brave the civil authority's snitches and attend clandestine masses. (Don' even think of asking me for details.)

I think to do this one must first understand what the person actually thinks. So questions must be asked.

So that hinges on the individual willingly giving up their agency. In other words: no you can't force your will on others. So success is dependent on the torturee agreeing to give up. — ISeeIDoIAm

I don't think one is willing. I think pain becomes and hopelessness becomes compulsion. I also don't think you choose to believe. He is hurting me so much so I choose to believe. In the broken, hopeless tortured state one finds one believes. I can't just choose to believe something to please someone. I can lie about it, but that's something else. There would be gray areas in there also.

Only brainwashing or the grace of God can change a core belief. Ormaybe what Kuhn calls anomolies can build up to the point where they compel a paradigm shift. — Phil Devine

Yes, experience can change beliefs. And other people can be part of that process, giving information, stressing that X happened, suggesting things to experience, reminding the person of what they said and why they believed something, suggesting reading, teaching certain skills that lead to experiences, challenging interpretations or dismissals and so on. I don't agree with the first sentence but the second is more expansive.