I am currently reading chapter 118 of the webcomic One-Punch Man, and came across this sentence:
I run across a lot of sentences with the particle で, and I never know when it's supposed to be used as "and" when it's used together with a noun, or "because". I don't know if this sentence is "(the person) made doubly sure, AND..." or if it is "BECAUSE (the person) made doubly sure, ...." or maybe it means something completely different.
Is there a rule or hint I can use to rule out one or the other?
So I asked A Japanese lady I tutor in English, and she said that this is a really weird grammar structure that mostly youth use, and seems to be kinda limited to be used only in Manga (unsure how genuine this is), but the meaning of the で particle here is connected to ダメ押し, meaning that the person who came/aimed at this test came here by being absolutely /doubly sure in their heart that they would win/pass, and it connects to もう一人現れた by meaning that another person who was absolutely/doubly sure they would win/pass in their heart also arrived.
Now I probably paraphrased this horribly, but at least now I know that it was neither of the ways of using the particles that I previously thought, and I can use that information to research it more on my own.