they … themselves/each other
Avant, ils s'entendaient bien mais maintenant, ils se disputent sans cesse.
They used to get along well, but now they argue constantly.
Ils s'aiment autant l'un que l'autre.
They love each other equally.
They're worrying for nothing.
I know they love each other.
Ils s'avancent à trois, ils prennent le pont.
The three of them advance, taking the bridge.
— Guerre et Paix (1968)
They hold each other in high regard.
Ils s'accordèrent pour commencer tôt.
They agreed to start early.
They secretly love each other.