12 We are not trying to commend ourselves to you again, but are giving you an opportunity to take pride in us, so that you can answer those who take pride in what is seen rather than in what is in the heart.

Read 2 Corinthians 5:12 Using Other Translations

For we commend not ourselves again unto you, but give you occasion to glory on our behalf, that ye may have somewhat to answer them which glory in appearance, and not in heart.
We are not commending ourselves to you again but giving you cause to boast about us, so that you may be able to answer those who boast about outward appearance and not about what is in the heart.
Are we commending ourselves to you again? No, we are giving you a reason to be proud of us, so you can answer those who brag about having a spectacular ministry rather than having a sincere heart.