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