The payout for a line bet in roulette, where a player wagers on six numbers across two adjacent rows, is 5 to 1. If the ball lands on any of the six chosen numbers, the player receives five times their original bet in winnings, plus the return of their initial wager. This payout offers moderate risk, as the line bet covers more numbers than individual or smaller group bets, providing a balance between potential reward and the odds of winning.