In *Kingdom Come: Deliverance 2*, completing the "Wedding Crashers" main quest can be tricky, especially when it comes to congratulating the newlyweds. Once it's clear that Otto von Bergow won't be attending Lord Semine's wedding, your focus shifts to wrapping up the quest and finding a new way to meet him. To successfully complete "Wedding Crashers," you must congratulate the newlyweds before leaving the celebration. However, locating Agnes and Lord Semine can be challenging as they seem to be missing from the festivities.
Before you set out to find Agnes, ensure you've completed any other tasks you want to do at the wedding. Once you start your conversation with her, it will lead directly into the quest's conclusion, transporting you to Trosky Castle. By this point, you should have already experienced the majority of the wedding's additional content, which occurs before the ceremony itself.
While mingling with the party-goers, you might ask if anyone knows the whereabouts of the newlyweds. However, since no one has an answer, you can skip this step and head straight to Agnes' location. If you previously stole some schnapps from the wine cellar, finding her will be straightforward.
Regardless of how your conversation with Agnes unfolds, it will inevitably lead to a man stumbling into the cellar and sparking a brawl that engulfs the entire wedding. You can either wait out the allotted time in the cellar or join the fray and fight whoever you can. The outcome remains the same, culminating in a cutscene where both Henry and Hans end up imprisoned at Trosky Castle.
That's how you congratulate the newlyweds in *Kingdom Come: Deliverance 2*. Your next main quest, "For Whom the Bell Tolls," awaits, where completing tasks within a time limit can boost your reputation, adding an element of urgency to your journey.