Nouns ending in -ie are usually feminine.
The suffix often names an abstract quality, an activity, or a discipline.
Is amie masculine or feminine?
l'amie
The masculine form is ami
The rule behind it
95.7% of -ie nouns are feminine
In context
C'est plus une connaissance qu'une amie.
She is more of an acquaintance than a friend.
Elle est plus une relation qu'une amie.
She is more an acquaintance than a friend.
J'ai trouvé en elle une amie sincère.
I found a true friend in her.