Let me answer you questions in reverse. There is a supply hose that is supposed to do what you are looking for. Problem is, they tend to shut off when they shouldn't. Avoid these. Many of us like the supply hoses that have the stainless steel mesh over them. Probably the safest connection is the old fashioned solid pipe that is fit to your toilet and supply valve. These are not really a DIY friendly connection because bending the tubing to fit requires experience to avoid kinking the tubing. Just a passing thought, do you know what your water pressure is? If it is too high, that could lead to premature failure of a flexible hose. High pressure is also hard on shut off valves in toilets, clothes washer, and dishwashers. Might be worth checking.