of his/her own free will
He did it of his own free will.
Adriano a embrassé Rima de son plein gré.
Adriano kissed Rima of his own free will.
Cedric est mort de son plein gré ?
Did Cedric die of his own free will?
— Harry Potter et l'Ordre du Phénix (2007)
Et de son plein gré, j'entends bien.
And of his own free will, I mean.
Elle fit la vaisselle de son plein gré.
She did the dishes of her own free will.
Chen Nian est venu de son plein gré ici.
Chen Nian came here of his own free will.
— Better Days (2019)