I’ve gotten the epilogue for her multiple times, and have always achieved the best outcome for Hise and Corval. Here are some of the things I did that I think helped with that:
- won the ship race in week 2 (gives a massive Hise approval boost)
- took a lead acting role in week 5 (I believe this gives Corval approval if you succeed)
- Told the Hise ambassador to negotiate with Corval for Henri’s relationship
- Spoke up at every opportunity in the Hise and Corval negotiations
- Suggested Hise and Corval form a joint navy
- Reminded Hise and Corval that they weren’t always that different (needs the History stat to succeed IIRC)
- Suggested that there are beneficial trade opportunities
- Promoted peace between Hise and Corval (didn’t need to spend any social influence to do so)
Hopefully this will get you the best outcome for Hise and the Cordelia epilogue!