Context: after waking up, Kamiigusa Misaki 上井草美咲 excitedly talks about her dream to Kanda Sorata 神田空太, who isn't as excited.
atashi, shourai wa oyome-san ni naritai! あたし、将来はお嫁さんになりたい！ I want to become a wife in the future!
{negoto wa nete kara iu no} ga kono sekai no ruuru desu yo 寝言は寝てから言うのがこの世界のルールですよ {Sleep-talking [is something you do] after sleeping} is this world's rule.
Kanda is saying she should only talk nonsense while sleeping, not after waking up.
mou shourai hajimatta-n-desu ka? もう将来始まったんですか？ The future already started?
shokuji ni suru ofuro ni suru soretomo... ma... wa... shi...? 食事にする？ お風呂にする？ それともま・わ・し？ [Which one do you want?] Food? Bath? Or... ma... wa... shi?
shinkon santaku 新婚三択 - newlywed three choices: a meme in which the bride welcomes her new husband home with three choices to choose from. Originally "what do you want to do? Food, bath, or me (wa-ta-shi)."
koko wa sumoubeya jaarimasen ここは相撲部屋じゃありません This isn't a sumo room.
In sumo, mawashi is the name of the loincloth that wrestlers wear.
