まつよいそうでしょう
待宵草でしょう
matsuyoisōdeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of まつよいぐさ

1. Probably waiting for the night.; Probably a night-blooming cereus.

Polite
Presumptive
Conjecture
Usually Written in Kana