Here is the step by step:
- Make sure you already have Anna on her Slut Route and Max Hearts
- Make sure you reject Nyxara and Master Zhen will tell you that he want to start gardening
- Go home and tell Anna about Master Zhen to help him with gardening
- Go to the Temple ( Torii Gate ) 3 times on the same day to progress the dialogues between Anna and Master Zhen
- Go inside the Temple to see Master Zhen giving a gift to Anna
- Tell Anna to show her appreciation to Master Zhen to initiate the Sharing Route ( Repeatable)