Here is the description of Droskar's Guiding Ring:
This gold ring is misshapen and uncomfortable to wear for long periods of time; inscribed on it is a crude symbol of a fire burning under an arch. Once per day, the wearer may use charm person. If Droskar is the wearer’s patron deity, any time the wearer crafts a magic item, she may choose to pay half of the item’s construction cost instead of the full cost. The wearer spends time working on the item normally, but at the time of completion there is a 50% chance that the item turns out nonmagical and worthless. For example, if creating a magic bracer that normally costs 1,000 gp to craft, the wearer may craft it for only 500 gp, but there is a 50% chance the wearer’s shortcuts and cheap materials result in a valueless, nonfunctional item.
The description of Divination:
Similar to augury but more powerful, a divination spell can provide you with a useful piece of advice in reply to a question concerning a specific goal, event, or activity that is to occur within 1 week. The advice granted by the spell can be as simple as a short phrase, or it might take the form of a cryptic rhyme or omen. If your party doesn't act on the information, the conditions may change so that the information is no longer useful. The base chance for a correct divination is 70% + 1% per caster level, to a maximum of 90%. If the die roll fails, you know the spell failed, unless specific magic yielding false information is at work.
As with augury, multiple divinations about the same topic by the same caster use the same dice result as the first divination spell and yield the same answer each time.
The description of Augury:
An augury can tell you whether a particular action will bring good or bad results for you in the immediate future.
The base chance for receiving a meaningful reply is 70% + 1% per caster level, to a maximum of 90%; this roll is made secretly. A question may be so straightforward that a successful result is automatic, or so vague as to have no chance of success. If the augury succeeds, you get one of four results:
- Weal (if the action will probably bring good results).
- Woe (for bad results).
- Weal and woe (for both).
- Nothing (for actions that don't have especially good or bad results).
If the spell fails, you get the “nothing” result. A cleric who gets the “nothing” result has no way to tell whether it was the consequence of a failed or successful augury.
The augury can see into the future only about half an hour, so anything that might happen after that does not affect the result. Thus, the result might not take into account the long-term consequences of a contemplated action. All auguries cast by the same person about the same topic use the same die result as the first casting.
Could one use Augury or Divination to predict the result of Droskar's Guiding Ring, allowing an almost 100% success rate with it?*
*Especially if you use something like Messenger of Fate to get a 100 percent success rate with your divination spells.