Everybody has to bless both rings. So show them to every villager.
Here are all the Heart Events:
1. After you defeat the final boss, speak to Rita
2. Go visit the girls in their tower on Whale Island
3. Talk to Rita again, then return to the tower and talk to Iris Blanche and Noire again. They will now live in Trampoli.
4. After both their LP has reached ten and they've been living in Trampoli for more than two weeks, talk to Eunice.
5. Speak with Lara
6. A day later, talk to Lara on the second floor of the inn
7. Wait a day, then talk to Lara again
8. After a week, talk to Selphy and she'll tell you about a new book
9. Find the book in the Rune Archives and try reading it
10. Talk to Kanno
11. Talk to both Irises to receive a set of rings. Show both rings to every villager to receive their blessings.
12. After you've completed this, talk to Kanno then to either Iris at nightfall.