the expression "bekeif" means "with happiness" (it is also used when someone tells you something great(and then u should add "sheihiye lecha/lach" and then "bekeif" and then it will mean- I hope you wiil have fun during doing what you just told me about)
mozes: wanna go to the movies?
mozes 2: bekeif.
mozes:I'm going to an hotel this weekend
mozes 2: seihiye lecha bekeif