The terms "trustworthiness" and "credibility" both go back to Lincoln and Guba's 1985 book, Naturalistic Inquiry. Even 40 years later, it is still the best source on this topic.
Qualitative researchers work hard to make sure their findings are trustworthy and credible. For example, they use different data sources or methods to confirm their results (this is called triangulation), and they often ask participants to review and validate the findings to ensure they truly reflect their experiences. They also describe the context and participants in great detail, so others can understand if the results might apply to similar situations. Additionally, they document their entire research process transparently, allowing others to follow their steps and verify consistency. Finally, they reflect on their own biases and how these might influence the study, which helps maintain objectivity. All these practices help build solid and reliable research that truly captures the complexity of human experiences.
As someone said before, the book from Lincoln and Guba, Naturalistic Inquiry, may also help you
Víctor Redondo Ribeill The various elements that you mention originate in Lincoln & Guba (1985) under the headings: triangulation, member checking, thick description, and audit trail. In addition, they emphasize "prolonged engagement" in the research setting.