よくぞ

よ

く

ぞ

Meanings

how admirably; how wonderfully; how skillfully

usually written using kana alonepolite (teineigo)

Polite, emphatic adverb expressing admiration or praise for an action. Often used in exclamatory or appreciative remarks. The ぞ adds a slightly formal or old-fashioned polite emphasis.

よくぞここまで成せい長ちょうしてくれました。
How wonderfully you have grown up to this point.
よくぞその難なん問もんを解ときましたね。
How admirably you solved that difficult problem.