Konstanze Natascha translate into english?

Answer 1

They are both german girl's names and cannot be translated into english.

Or did you mean, how to create english version of these german names?

That would be Conny and Natasha.

Natasha is of course not genuinely german, it really is a russian name. But it is given to german girls for about 100 years now, and you will find a Natascha in almost every classroom or bus nowadays.