If I slip on something in a store, am I guaranteed a recovery?

No. Just because there is something on the floor that causes you to fall does not mean that the store is liable. It must be proven that the store either knew that it was on the floor or should have known that it was on the floor for them to be found negligent. Also, the law places the burden of walking with reasonable care on you the visit and if the substance is noticeable to the extent that a reasonable person using ordinary care should have seen it then you may be contributory negligence which would bar you from any recovery.