Most choices in dialogue result in different affection outcomes from +1-+2 hearts/Love or so to +1♥️ for each sister to +1 bravery and possibly a ♥️ as well. So, try each option in conversations and you should be able to reach it… I missed the last bravery checkpoint as well since I thought I’d need another heart for one of the sisters and when I realized I didn’t feel like going back through at the time… hopefully I didn’t miss a scene but I probably did lol