I would need to understand the following:
They tried very hard to mislead the interviewer, for the stakes were very high.
What is the meaning of the second part of the sentence?
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First, replace for with because. Using for instead of because or, perhaps, since is a bit old-fashioned and formal. However, it might also be the standard idiom in some dialects of English.
High stakes is a gambling metaphor which means the gambler is going to win or lose a lot of money in the game.
In an interview with a potential employer, misleading the interviewer may lead to the interviewee's getting the job: if the job's important, then the stakes are high.
In an interview with the police, misleading the interviewer may lead to not being suspected of having committed a crime. One's freedom is at stake, so the stakes are very high.