To become allies you need two conditions to open up the chance to convince her, then pass a persuasion check:
During her friend date on week 6, you will get an extra set of choices if you saw the secret acene in the garden that week, all the weavers scenes in previous weeks, and have enough respect+friendship:
- I will be satisfied...
- Truthfully,..... Friendship + | Respect ++
- I'm worried, Avalie (Ethical only)
-- I suppose... - Avalie will not become your ally
--I don't think that...
---Let the subject drop. - Avalie will not become your ally
---Attempt to convince her
Pass 455 > Persuasion- "...You are a manager of miracles, Charname." - Avalie will become your ally
Fail < 455 Persuasion - Avalie will not become your ally