Here is the full list of all 29 Scarlet Maiden achievements.
Slay 200 enemies in one run
Completer the quest ‘It’s a Strap’
Complete the quest ‘Green Delight’
Level Faelina to level 5
Defeat Queen Lily
Complete the quest ‘Magic Flute’
Slay 100 enemies in one run
Defeat the Grand Archivist
Gain 100000 sin total
Level up to level 50
Earned after 10th run
Level Roman to level 5
Level Bruce to level 5
Find 50 items in one run
Gain 15000 sin in one run
Defeat the Earth Mother
Complete the quest ‘Masquerade’
Complete the quest ‘Steamy Contraptions’
Level up to level 10
Find 20 items in one run