I was sitting at a table with 2 ladies and was handed a white business size envelope with an enormous amount of money in it. The envelope looked like it had been sealed but someone had cut it open with a letter opener. It was so full of money that it was stretched wide open.
'Kathy' showed up and heard that I had received all this money and I felt she was not happy I had it and wanted it back. I did not give it to her. End of dream.
This weekend I watched "Goodbye Charlie," with a scene much like that...the protagonist was assumed to be rich because widowed, the other women were being catty. (Many more twists to that.)
I think of Kathy as Irish-based name, even though it's widespread. (UK )
Pure/chaste, ancient Greek “katharós/κᾰθᾰρός” -- could imply the recipient was not involved in any questionable sourcing of the money, but maybe it originally was meant to belong to her. Perhaps you represented your country refusing to trace back correct sources.
Business envelopes have a simple layer of security to hide contents like checks.
This might have nothing to do with your dream, but worth a watch... seems to parallel on a large scale.