expression
Rare expression meaning 'to tell the truth' or 'in fact', used to emphasize a statement. Often appears as a set phrase.
まったくのところ、彼の言うことは正しい。
To tell the truth, what he says is correct.
まったく is a common adverb meaning 'really' or 'completely'. まったくのところ is a rarer, more emphatic phrase meaning 'in fact' or 'to be honest'.
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.