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〜じゃろう: probably (old speech)
Character speech · 02 Endings and verbs
Old-man version of だろう, a guess.
Plain form + じゃろう; noun and na-adjective attach directly. Often shortened to じゃろ. Paired with わし and のう. Dialect users in the west also say じゃろう.
Examples
明日は雨になるじゃろう。
It will probably rain tomorrow.
そなたも疲れたじゃろう。
You must be tired too.