Magic words: Ace Attorney-style orange text & Umineko-style red text.
This is pretty much what it says on the tin. Moa often makes references to other games throughout Hatoful Boyfriend and these are a couple of them that show up in the Bad Boys' Love route that I'm taking Shuu from.
As a side note, I have never actually played an Ace Attorney game OR an Umineko game so my knowledge of these meta-devices are based off of wiki-browsing and how they're used in BBL. So here is my understanding of these meta-devices:
Orange text is used to highlight or emphasize key phrases and terms.
Red text is always factually true. (Shuu can't use it to create swords or whatever though.)
Both of these things operate on a meta level so... I'm not really sure how they'd translate into face-to-face interactions. Orange stuff draws attention and anything said in red feels more truthful to characters? Or feel free to just ignore it and enjoy it as a player.
Corrections and links to additional info are much appreciated. o/