Breakdown of kanojo wa kotae ga tadashii to kakushinshita.
Questions & Answers about kanojo wa kotae ga tadashii to kakushinshita.
は marks 彼女 as the topic: the sentence is talking about her and then saying what happened with respect to her.
So the structure is roughly:
- 彼女は = as for her / she
- 答えが正しいと確信した = became convinced that the answer was correct
If you used 彼女が, the sentence would sound more like you are specifically identifying her as the one who was convinced, often in contrast to someone else.
Because 答え is the subject of the embedded statement 答えが正しい.
That part means:
- 答え = answer
- が = subject marker
- 正しい = correct
So 答えが正しい means the answer is correct.
If you used を, it would suggest 答え is a direct object, but 正しい is an adjective, not a verb that takes a direct object. So 答えを正しい would be ungrammatical here.
