In texting, "rus" typically stands for "are you serious?" It's often used to express disbelief or skepticism about something someone has said. The abbreviation is part of a broader trend of using shorthand in digital communication to convey emotions or reactions quickly.
FR in texting means "for real" as an exclamation.
ths stands 4 this in texting
imf
Call Me
Yyp
Hurry Back
BTR
haven't had sex
laugh out pee
Cracks me up
no one cares
Face Time