What did he testify to Congress about? Can you please elaborate how it will be obvious that he lied if, for example, he blacks out certain information that he did not provide to Congress, since he did not give the entire report to Congress?
Why do you believe he behaved in good faith to Congress given the massive nature of the report?
*edit*
I also notice you didn't answer the question. If I may ask again, do you personally trust Barr's word at face value?
We don't have to trust him. He testified that "peripheral third parties" would not include any public officials at all. The statement wasn't ambiguous. Every redaction will be color coded and justified. That plus context will make it very, very obvious if information about Trump is redacted.