Here is the full list of all 30 Wife Quest achievements.
START A NEW JOURNEY IN WIFE QUEST
BE DEFEATED IN BATTLE AGAINST MORGANNA IN THE GRASSLANDS
DEFEATED MORGANNA IN GRASSLAND
DISCOVER MORGANNA'S PLAN AT YMIR'S STORE
BUY THE FIRST SET OF UPGRADES, SWORD, ARMOR AND MAGIC STONE
BUY A BAG AND A POTION AT YMIR'S STORE
DEFEATED TANIA IN FAIRY FOREST
COMPLETE THE FAIRY FOREST'S YMIR CHALLENGES
DEFEATED RED IN DEEP CAVES
COMPLETE THE DEEP CAVES' YMIR CHALLENGES
DEFEATED SILY IN HELLCANO
COMPLETE THE HELLCANO YMIR CHALLENGES
DEFEATED FRIA IN FREEZING PLAINS
COMPLETE THE FREEZING PLAINS'S YMIR CHALLENGES
DEFEATED MORGANNA IN MORGANNA CASTLE
COMPLETE WIFE QUEST ON NORMAL MODE
START A NEW JOURNEY ON MAGIC MODE
COMPLETE WIFE QUEST ON MAGIC MODE
FOLLOW ALL THE DIALOGUE BETWEEN MIA AND YMIR
BUY ALL UPGRADES, WEAPONS, ARMOR AND MAGIC STONES AT YMIR'S STORE
BUY ALL BAGS AT YMIR'S STORE
COLLECT ALL MUSICAL NOTES
COLLECT ALL IMAGES
GET ALL PUNISHMENT ANIMATIONS
COLLECT ALL BOSS CHESTS
COLLECT ALL GREAT HEARTS
COLLECT ALL GREAT CRYSTALS
BUY ALL ITEMS AT YMIR'S STORE
COMPLETE ALL YMIR'S CHALLENGES
COMPLETE THE WIFE QUEST MINI-GAME