ことになる (koto ni naru)
Meaning: it has been decided that…, it has been arranged so that…, it turns out that…
How to use the: Verb-casual, non-past + ことになる
Use when showing that the event has been sorted and decided. Use when you want to say: from a certain situation, it is obvious that it is like that
Kondo Ōsaka shisha ni iku koto ni narimashita.
This time I decided to go to a branch office in Osaka
Rainen Nihon ni hikkosu koto ni narimashita.
I decided to move to Japan next year
Isshokenmei ganbaranakereba, kōkai suru koto ni narimasu yo.
If you don’t try your best, you may regret it in the future
This sentence pattern is frequently used because when expressing the meaning of a decision, it is not necessary to have the person / factor that made the decision in the sentence. For the meaning of “become” there is a hypothetical situation ahead or an explanation of the reason for that.