正せい確かくに言いうと

expression

to be precise; strictly speaking

Used to clarify or correct a previous statement, adding precision. Often appears at the beginning of a sentence or clause.

• 正せい確かくに言いうと、彼かれは昨日きのうではなく一昨おとと日い来きた。

  To be precise, he came the day before yesterday, not yesterday.

• 正せい確かくに言いうと、その本ほんはまだ読よんでいない。

  Strictly speaking, I haven't read that book yet.