What is the grammatical construction of the clause "Emotions that Maria had thought were buried deep enough ..."

Question

Something in that should have upset Maria, but all she could concentrate on was the pain and anguish that ravished her body. It was like a silent demon had lay dormant inside of her and fed on all the pain that had ever been inflicted on her and those she holds most dear. A demon that knew how to bide its time and unleash its festering anger on anyone that was responsible for its creation. Was the inner demon part of Maria? Or was it separate and just used the woman's body as a place to hibernate? Only Maria could answer those questions, and she was in no condition to consider them. So many emotions fed that silent demon. Emotions that Maria had thought were buried deep enough so they could not betray her at the worst possible moment.

"Emotions that Maria had thought were buried deep enough so they could not betray her at the worst possible moment."

Is Emotions the object of thought? But how do you just "think" emotions? It is ungrammatical.

Or perhaps, that Maria had thought were buried deep enough is just a relative clause modifying Emotions? But this is also ungrammatical, there's no main clause in the sentence now. Is the original sentence grammatically correct in the first place?

Answer 1

This question has basically answered in the comments, so I will not explain in detail what has already been said.

The part in bold is indeed not a full sentence. It is an appositive which is normally marked by comma(s), but in literature, peculiar punctuation like this can be used. The apposition is a Noun Phrase consisting of the head Emotions and the relative that Maria had thought were buried deep enough so they could not betray her at the worst possible moment. It is this relative that seems to be confusing you.

1. Emotions = subject of the verb were buried
2. that Maria had thought were buried deep enough so they could not betray her at the worst possible moment. = relative clause, within which:

• [that they] were buried deep enough = direct object of had thought
• so [that] they could not betray her at the worst possible moment = consecutive adjunct establishing the effect of were buried deep enough.

So the object of had thought is not emotions but the object clause were buried deep enough which could be replaced by a non-finite infinitive clause:

Emotions that Maria had thought to be buried deep enough so they could not betray her at the worst possible moment.

Answer 2

There is nothing wrong in that sentence. But, sometimes, rephrasing can help understand things better : Maria had thought/considered (that) her emotions were buried so sufficiently deep that they could not betray her at the worst possible moment.