“Best efforts” is a legal term. Its definition can vary from state to state, but it is not just, “oh we tried, sorry, lol” and it defines the highest standard of implementation in all jurisdictions.
The clause acknowledges that success depends on variables nobody fully controls: market conditions, regulatory approvals, third-party cooperation. So instead of promising a result, the party promises effort of a particular quality. Courts then evaluate that effort after the fact, which is where things get complicated.
From https://fedlaws.org/best-efforts-standard-in-contracts-ucc-r...