A simple mundane oath is common in the realms. Betrayal of these compacts has no direct impact on the breaker of the oath (other than mundane and secular). Helca though, has a fairly well known property of a Sanctioned Oath. The very world itself seems to empower the bond of Sworn Word or Sacred Oath – its referred to as Sworn World Oath. A character willingly entering into a compact and sealing it with their sworn word/oath and adding “may the very world itself forsake me if this bond be broken.” It need not be 2 ways, most times it is a pledge from one party to another. Though devoid of any Essence cost, and only functional on Helca, the oath is held on the threat of Despondency. Once broken or abandoned, if it was a pledge of fealty from one person to another, the party pledged to will known of it when it happens. The greatest known example of this type of oath is The Godspeak Accord.
A Sanctioned Oath, once broken, will impose Despondency on the oath-breaker until a Long Rest is had, at minimum.