The term "one damndests" is used to express a strong emphasis on something being difficult, challenging or frustrating. There are several synonyms that can express the same level of intensity as "one damndests". "Most darned" and "most confounded" are two alternatives that are equally forceful. Other options include "extremely difficult", "most challenging", and "incredibly frustrating". These synonyms effectively convey the same sentiment as "one damndests" and can be used interchangeably. Regardless of the phrasing, these expressions all indicate a high level of difficulty or struggle and are useful in various writing contexts.