At one time or another, your business will have to borrow some money. It can take a pretty substantial business before a bank will lend you funds without requiring your personal guarantee to pay it back. No question with a sole proprietorship. The business isn't separate from your personal wealth. You're on the hook.
All partners are on the hook for partnership debts.
A corporation can protect its shareholders if lenders are willing. But they often require personal guarantees. Here again, a corporation may not afford you the protection you were hoping for. If your business is really small, it won't matter how you structure it. If you are the only owner, it doesn't matter if you are a sole proprietor or a corporation.