Nouns ending in -ure are usually feminine.
The suffix often marks a result, state, or collective.
Is meilleure masculine or feminine?
lameilleure
The masculine form is meilleur
The rule behind it
94.3% of -ure nouns are feminine
In context
Je pense que c'est la meilleure manière.
I think it's the best way.
Des deux histoires, la seconde est la meilleure.
Of the two stories, the latter story is better.
Il a reçu une meilleure note que nous.
He got a better score than us.