During The Beast of White Orchard, you will be faced with your first time-constrained dialogue option in which you need to make a quick decision regarding your reward. The griffin is dead, and the Nilfgaardians are willing to pay you, but what moral choice will you make? Truthfully, your decision has no lasting consequence, but you might want to know the difference in rewards!
Geralt takes the coin, and the Nilfgaardian looks smug.
Geralt walks away without saying a word.
I recommend you turn down the coin, as the extra XP is far more valuable than the coin that you can get through easy money exploits (like the guide linked here). Plus, it makes narrative sense that Geralt wouldn't take money from Nilfgaardians.
Although a witcher doesn't work for free, Geralt's payment was actually information on Yennefer, as agreed. The Nilfgaardian offering extra payment is a power move, as he clearly wants to test Geralt's morality to see if he's willing to take money when the people of the Northern Realms are starving, so I'd recommend leaving the coin to beat the Nilfgaardian at his own mind games.
Taking the coin or turning it down has NO consequence on the story or any future quests, so feel free to make your own choice, as this will never come back around to bite you.
سەرچاوەی فەرمی بە زمانی ئینگلیزی: https://gamerant.com/the-witcher-3-take-or-leave-coin-decision-griffin-kill/