Sometimes pretending to be someone else with 〜ことがある
Grammar Explanation: Sometimes with 〜ことがある

Sacchan and Kotoha notice Yui walking with a couple of her friends from school. The two decide to sneak and follow after them. Sacchan notices Yui doesn’t act quite the same with these friends as she does with Sacchan and Kotoha.
- さっちゃん:
- 「潜入作戦
( とかで別人( になりきることがあるかもしれないから」- “Maybe it's because she's in an undercover operation or something that she sometimes pretends to be a different person....”
- Literal: “Because maybe, during an infiltration mission or something, there are times when she fully becomes a different person...”
- 「学校
( の時( の結衣( は結衣( らしさを消( してすごしてるのかもしれない」- “...that Yui at school might be trying to hide her true self.”
- Literal: “Maybe Yui when she's at school spends her time erasing her Yui-ness.”
- “Maybe it's because she's in an undercover operation or something that she sometimes pretends to be a different person....”
Key Points
- Here 別人
( になりきることがある means “there are times when she fully acts like a different person”. - It describes something that happens on some occasions, not a one-time event happening right now.
- 「なりきる」 is stronger than just “become”. It means to thoroughly take on a role or persona.
- The idea is “Maybe it’s because she sometimes has to pretend to be someone else…”
- 「から」 links that imagined reason to the following speculation about Yui hiding her usual self at school.
- 「ことがあるかもしれない」 means even the “sometimes does that” part is only a guess.
- The next line ends with のかもしれない, so Sacchan is building a theory rather than stating a fact.
Vocabulary
時 (Time)
時
( refers to time, as in duration or a specific moment.作戦 (Strategy)
作戦
( means strategy, operation, or tactical plan. It is a battle plan whether literal or figurative.潜入 (Infiltration)
潜入
( is a term that refers to entering a place covertly, out of sight of others, or sneaking in secretly. It is used in situations such as infiltrating an organization while concealing one’s true identity for espionage or investigative purposes, or when secretly entering a hidden location.別人 (Different person)
別人
( refers to someone who is not the same as a particular individual, or to another person who is not that individual. It is also used figuratively to describe a situation where a person’s appearance, personality, or attitude has changed dramatically compared to before.
See Also
- Grammar: Might with 〜かもしれない
- Kanji: Entering and putting in with 入
- Kanji: People and persons with 人