はたして彼の話は本当だろうか。

English Translation

Can his story be true?

はたして is also spelled as 果たして, and I guess we use 果たして more often.

If 果たして is in an interrogative (question) sentence, it adds the nuance of “I wonder how the situation will be developed eventually” or “it’s unpredictable, but…”. As you can imagine from 結果 (result), 果たして is basically “eventually”.

I’m afraid the English translation doesn’t fully convey the nuance of {{果たして}}, and it’s hard for course takers to answer this exercise.