ことになるBe decided or come to be the case
ことになる presents an action as a settled decision, arrangement, assignment, or result. It focuses on what has been settled rather than on the person who chose it.
The viewpoint of the construction
ことになる does not necessarily mean that events changed by themselves. A committee, company, family, or individual may have made the decision; the sentence simply presents the decision from the side of the settled result.
Decisions, assignments, and outcomes
The construction works naturally for an institutional decision, a personal assignment, or an outcome produced by circumstances.
会議の結果、四月から新しい制度を始めることになりました。
Following the meeting, it was decided that a new system would start in April.
AnalyzeThe institution's settled decision is presented without naming the individual people who approved it.
私は受付を担当することになりました。
I have been assigned to handle reception.
AnalyzeThe speaker reports an assignment rather than claiming it as a personal choice.
父が入院したので、家族旅行は中止することになった。
Because my father was hospitalized, the family trip ended up being canceled.
AnalyzeThe circumstances led to this outcome, even though people still made the practical decision.
Choosing the final form
Use ことになる when describing what the arrangement means or what will now result. Use ことになった or ことになりました when reporting that the decision or outcome has already been reached.
話し合いの結果、来週もう一度会うことになった。
After discussing it, it was decided that we would meet again next week.
AnalyzeYour decision or the settled result?
ことにする foregrounds the subject's own decision. ことになる foregrounds the result that was settled, even when people were responsible for settling it.
私は来年、留学することにしました。
I decided to study abroad next year.
AnalyzeThis explicitly presents the choice as the speaker's decision.
会社の選考で、私は来年、留学することになりました。
Through the company's selection process, it was decided that I would study abroad next year.
AnalyzeThis presents studying abroad as the settled outcome of the company's selection.
More examples
卒業後は、姉の店で働くことになりました。
It has been arranged that I will work at my sister's shop after graduation.
Analyze抽選の結果、私が代表として発表することになった。
As a result of the draw, I ended up being the one who would give the presentation as our representative.
Analyze台風のため、試合を翌週に延期することになりました。
Because of the typhoon, it was decided that the game would be postponed until the following week.
Analyze予算が足りず、今年は新しい機械を買わないことになった。
Because the budget was insufficient, it was decided that no new machinery would be purchased this year.
Analyze話し合いで、毎週金曜日に進み具合を確認することになりました。
In the discussion, it was agreed that progress would be checked every Friday.
Analyze電車が止まり、その夜は駅の近くに泊まることになった。
The train stopped running, so I ended up staying near the station that night.
Analyze