If there is no direkt way to mate or winning the rook by a skewer or a dicovered check,
there is no way to win this against a well playing opponent. It's still possible to win this game against an opponent who blunders (maybe the opponent is very low on time) or just on time. With enough playing strength and some time on the clock there will be a threefold repetition, a draw by 50 moves rule, the exchange into a king vs. king draw or just a draw agreement in most cases.
Winning K+R against K is the easy part. Everyone should know a safe method to do. Even if this method takes 20 instead of 5 moves.
If you want to insist that Black can lose if he plays idiotically, why not just have him blunder the Rook at once and be done with it?
You got a faster mate?