Wolfox

My sister asks me if I could potentially not eat some of a certain kind of cookie each day. I say "I will". She keeps Explaining why while I already said that I would, and I say "I will" a second time. She STILL keeps explaining because I have to listen while she doesn't, and I say "I will" a THIRD time. AND SHE STILL explains why. I ask how many times I have to say that I will remember to not eat too many of them on my own before she realizes that I won't eat too many. And then after around 5 times of me saying "I will" instead of thanks, I get thanked with an "As long as you don't forget.". So, how many times does one need to say "I will" till it's generally accepted that I said "I will"?