What does "provably fair" mean?
It is the system Stake Originals use so you can mathematically verify that each result was fair and not manipulated. Before each round a hashed seed is created; later you can review it and confirm the result was not altered. That is why these games earn so much trust versus regular slots.
RTP and house edge: the honest part
RTP (Return To Player) of 99% means that, statistically long-term, the house keeps ~1%. Among the lowest on the market — much better than slots (3-5%)— but it still exists. There is no game you will "beat" long-term; what you can do is shrink that edge with 20% rakeback from code Tg77L5Oj.
The lower the house edge, the more your bankroll lasts and the more rakeback you generate per dollar wagered. That is why Originals are the best base for smart play. Estimate your return in the bonuses.