義理 ぎりのお にいさんでしょう
girino oniisandeshō

Noun
Desu Copula

Expresses probability in a polite manner ("probably…") of 義理のお兄さん

1. Probably your brother-in-law.; Probably someone you have a familial obligation to, like an older brother figure.

Polite
Presumptive
Conjecture