also: のちになって
expression
afterwards; later on; at a later time
Used to indicate that something happens after a certain point in time, often with a nuance of 'eventually' or 'in hindsight'. Common in both spoken and written Japanese.
後になって、彼の言っていたことが正しかったと分かった。
Later on, I realized that what he had said was correct.
後になって後悔するかもしれないよ。
You might regret it afterwards.
後で is more casual and commonly used for 'later' in everyday speech, while 後になって often implies a more significant passage of time or a reflective hindsight.
A set phrase composed of 後 (あと, 'after') + に (particle) + なって (the te-form of なる, 'to become'), literally 'having become after'. The reading のちになって is a formal/literary variant.