That's correct, no one could get that huge amount of money through loan here, even if he will convince the lender that the bet is guaranteed to win, they will never believe because in real life, it does not exist, it's just only the words coming from the scammers.
Precisely, a guarantee bet is not something that anyone can easily been proven, maybe a part of a deeper mafia, but they will never share that information. They will protect it not to be leaked. It's a lot of money that in stake and no one from that particular group will take that risk being burned if they mistakenly exposed their business. (not proven, but rumors think it does exist)
The right thing to do, is collateral the house and lot and ask for a loan, but probably only available through financial institutions like banks.
If you have that properties, you use it as collateral to collect the funds that you needed, if you are sure with that kind of decision
no one can stop you, but always put in mind that shit can happened and learning things the hard way is something that you won't
love to experienced.