Roke means: I may not be showing it right now, but that's hella sick. Roke is a term similar to "cool," "sweet," or "nice" but with a more muted happiness.
i.e. when you're excited for someone but you're also a little depressed, so you want to show them you're happy for them even though you seem down.
"Oh snap, I just won a raffle!" "Roke, dude."
"Just got my tax returns, imma go buy a McDouble." "Oh hell yeah, man. That's roke."