To end up being with 〜ことになる
Grammar: Time and Sequence » 〜ことになる
〜ことになる says that circumstances, rules, or other people bring about a result or decision. When the speaker makes the decision personally, use 〜ことにする instead.
Further Reading
- ことになる/する & ようになる/する (maggiesensei.com)
Examples
Came to be studying with us with 〜ことになる

A new student joins Conan’s elementary school classroom. The teacher introduces her.
- 先生:
- 「今日
( からみんなと勉強( する事( になった、灰原( 哀( さんです!」- “This is Ai Haibara. It came to be that she'll be studying with us starting today.”
- 「みんな仲良
( くしてあげてね!」- “Everyone be friendly with her!”
- “This is Ai Haibara. It came to be that she'll be studying with us starting today.”
To end up betraying with 〜ことになる

Makoto explains to Misuzu that he’s been looking into various things since meeting Kanami, such as housing for orphans. However, he realizes what Kanami wishes for is to have her once-kind brother back to the way he used to be.
- 真
( : - 「俺
( が引( き離( してしまったら」- “If I separate her from him...”
- 「叶
( 実( ちゃんを傷( つけて…… 裏切( ることになる」- “...I'd be hurting Kanami... I'd end up betraying her.”
- “If I separate her from him...”
To end up cleaning for you with 〜ことになる

Urushi and Ayumu give their makeshift clubroom a cleaning to welcome potential new members. Considering that Urushi was the only club member before he joined, Ayumu remarks how she alone had cleaned the room for his sake last year.
- うるし:
- 「まぁ 結局
( 」- “Well, in the end...”
- 「お前
( しか入部( してないからそういうことになるか」- “You were the only new member, so it ended up as you say, huh?”
- “Well, in the end...”
Supplemental Examples
Try finding this grammar in the following examples: