fickle
US /ˈfɪk.əl/
UK /ˈfɪk.əl/

1.
inconstant, changeant
changing frequently, especially as regards one's loyalties, interests, or affection
:
•
The weather here is notoriously fickle.
Le temps ici est notoirement changeant.
•
She's very fickle, one day she loves you, the next she hates you.
Elle est très inconstante, un jour elle t'aime, le lendemain elle te déteste.