???
I start every day at 0-7. I'm forced to have sex every third day (ruining the pacing). There's definitely no resetting willpower.
The fact that you start at different willpowers each day means your willpower has reset.
It can then lower by the virtue of one of the curses (like eyes of greed).
Your real problem seems to be that you've done ALL the corruption content, locking yourself to critically low willpower, and are at a spiral that is going to end with the "bad end", once it is implemented.
However, to go back to the original question, even if you have only 1 willpower at day start, you can pay whatever amount of money you need to one NPC as long as you don't use that 1 willpower before talking to the NPC.
If you're feeling stuck due to the corrupt choices you've made, maybe try a NG+ run.