How do we know that Paul was a trustworthy messenger of the gospel?

In 2 Corinthians 1:12, Paul explains how his conscience bears witness to his conduct among the Corinthians, stating that his actions were characterized by simplicity and godly sincerity, not by fleshly wisdom. The accusations against him stemmed from his failure to visit them, which some interpreted as inconsistency. However, Paul emphasizes that his intentions were consistent with God’s purposes, highlighting that his message was never 'yea and nay' but consistent and faithful. By grounding his testimony in God’s grace, Paul asserts that his ministry remains unwaveringly aligned with the gospel, establishing his reliability as a servant of Christ.