であろう

expression

will; probably; I think; it seems

Formal or written volitional/presumptive form of である (to be). Expresses the speaker's conjecture, intention, or hope about a state or event. Often used in formal speech, writing, and set phrases.

• 明日あしたは雨あめであろう。

  It will probably rain tomorrow.

• 彼かれの言いうことは本ほん当とうであろう。

  What he says is probably true.