If GF don't admit mistake, I still think she's at fault, that must be my fault!

如果女友不认错，我还认为她有错，那就是我的错！

youdao

He was loath to admit his mistake.

他不愿承认自己的错误。

《牛津词典》

I freely admit that I made a mistake.

我爽快地承认我犯了错误。

《牛津词典》

I go the most direct way. Anyone who eats crow has to admit a mistake or defeat.

VOA: special.2010.06.13

Too embarrassed to admit his mistake, he decided to blame the Jews and become a local hero.

CENTERFORSECURITYPOLICY: Agents of influence

When the Spanish National Police got the real perpetrator, an Algerian named Ouhnane Daoud, the FBI had to admit its mistake.

FORBES: Forensic evidence doesn't always tell the truth.

"This decision by the PSNI to issue an unreserved and unconditional apology to myself and my wife and family for the indignity and trauma inflicted on us by this unwarranted raid on our home vindicates what I said at the time - the PSNI got it wrong and should publicly admit their mistake, " he said.

BBC: Derry mayor wants officer who ordered search sacked