> accent? Structure? I have no idea

Its a combination of many things, intonation and delivery, politeness (formality, honorifics etc.) level, word choice, particle choice.

Its known as onnarashii (女らしい) speech.

Its a historical thing which is gradually falling out of use. These days you tend to only mostly find it in situations where the politeness levels are needed/expected (e.g. hospitality industry).