Rare expression meaning 'to tell the truth' or 'in fact', used to emphasize a statement. Often appears as a set phrase.
To tell the truth, what he says is correct.
Rare kanji variant using 所; less common than 全くのところ.
Combination of まったく (entirely) and のところ (a phrase indicating 'the point is'). The exact historical derivation is uncertain, but it functions as a set expression.