diligently, assiduously
Ils travaillent aussi assidûment qu'une ruche d'abeilles.
They work as diligently as a beehive.
Il a étudié assidûment; autrement il aurait échoué de nouveau.
He studied diligently; otherwise he would have failed again.
C'est une mission qu'ils doivent accomplir assidûment.
It's a task they must carry out diligently.
— Demon Slayer : Kimetsu no Yaiba - Le film : Le train de l'Infini (2020)
J'espère que mon fils va se mettre à étudier assidûment.
I hope my son will start studying diligently.
Le professeur lui dit de travailler son anglais assidûment.
The teacher told him to work on his English diligently.