"The girl of my sister is my niece."

Translation: Fata surorii mele este nepoata mea.

[CAQu91]

'The daughter,' not 'the girl'

[LilFluent]

I am confused as to why "my sister" is in plural for the romanian translation but in singular for the english? I can recognize that "sister" is in singular genitive dative, but the "mele" throws me off...

[crbratu]

It is not in plural but in singular genitive. You are misled by "surori" that is indeed the plural of "soră" but here we have "surorii" (double i). As a side discussion Romanians debate which of "surorii mele" or "sorei mele" is better. Both forms are used.

[Victor111671]

But unfortunately "sorei mele" is not accepted((

[DanielOrth4]

Fetița sorei mele... Should be accepted