Here is the full list of all 50 Love Tavern achievements.
Complete 4 chapters of Nozomi
Complete 4 chapters of Toyo
Complete 4 chapters of Flann
Leona's story
Complete 4 chapters of Miwa
Complete 4 chapters of Tamiko
Cook 600 dishes
Complete dungeons 50 times
Cook 120 perfect dishes
Collect 1000 ingredients
Clean 100 times
Provide 100 onsen services
Provide 100 sauna services
Provide 100 massage services
Complete 4 chapters of Emily
Earn 7777 gold
Learned 20 cooking recipes
Hire all unique staffs to the tavern
Hire 10 five-star staff members
Collect 1mil Gold
Hire 30 staff members
Welcome Nadia to the tavern
Build 40 of any type of room
Served 1500 customers
Welcome Emily to the tavern
Complete 4 chapters of Lilith
Complete 4 chapters of Natsumi
Complete 4 chapters of Izumi
Welcome Leona to the tavern
Welcome Lilith to the tavern
Welcome Miwa to the tavern
Build a single cleaning room
Welcome Toyo to the tavern
Hire 1 five-star staff member
Welcome Natsumi to the tavern
Build a single onsen room
Welcome Sakura to the tavern
Build a single storage room
Welcome Flann to the tavern
Build a massage room
Build a single sauna room
Welcome Tamiko to the tavern
Welcome Slyvia to the tavern
Welcome Nozomi to the tavern
Build a single hunting room
Build a single dining room
Welcome Izumi to the tavern
Hire a staff member
Build a single dormitory
Build a shop