"Glumești?"

Translation: Are you joking?

[R.White]

Sounds like Ukrainian "glumytysia", same meaning if not of a more negative connotation

[EmmaMitche89062]

"Are you kidding (me)?"

[Chibirexy]

Anyone know if this could be translated as "You jest"?

[Ululare]

wiktionary says

a glumi (..)
1. to joke, jest

so I'd say it probably can.