Direct answer
Objectives follow journal display order. Some depend on your choices; follow the active objective in the game.
Result
It turned out Sigi Reuven was none other than Sigismund Dijkstra, former head of Redanian intelligence and a man well-known to Geralt from past adventures. In an atypical bout of ignorance, Dijkstra had no inkling I was involved in the theft of his gold. He treated Geralt's appearance as a fortunate coincidence and offered him a handsome sum in return for help finding his stolen wealth - and the thief who had stolen it. Geralt and Dijkstra thus both wanted to find the exact some person - yours truly - albeit for entirely different reasons. Seizing this bit of good fortune, Geralt accepted the offer and hoped against hope Dijkstra wouldn't catch on to his double dealing.
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