In the Witcher 3's "Ashen Marriage" quest, set in Novigrad, Geralt assists Triss Merigold and her fiancé, Castello, with wedding preparations. His tasks include ridding the canals of monsters, procuring alcohol, and selecting a wedding gift for Triss. The gift choice impacts Triss's response; a memory rose, a callback to Witcher 2, elicits a strong emotional reaction, unlike less sentimental presents.
However, Dijkstra's revelation of Castello's connection to witch hunters throws a wrench into the proceedings. Castello is revealed to be acting under duress, blackmailed by the hunters who threaten to expose his illegitimate daughter from a previous marriage.
Geralt can choose to reveal this truth to Triss, either privately or with Castello present. Regardless, the wedding is called off. Triss is either disappointed in Castello's deception or appreciative of his honesty, ultimately deeming the marriage premature.
This unexpected turn could have significantly deepened Geralt and Triss's relationship and provided richer character development for supporting characters.