旧姓 きゅうせいではありませんでした
kyūseidewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 旧姓

1. Was not formerly [my/her/his/their] family name.; Was not called [my/her/his/their] former name.

Past/Perfective
Negative
Polite
Formal Register