for the love of me

1. Despite my best efforts; no matter what. I just can't, for the love of me, understand why you would do something so reckless? I know I left my keys here somewhere, but I can't for the love of me find them. I can't for the love of me get the lid off this jar. Do you want to have a try?

2. obsolete Because the person being referred to loves the speaker. You would die for the love of me? No, John, I cannot let that happen! My father has never done anything for the love of me or any of his other children! Please, no! I won't allow you two to duel for the love of me!