tell it to him/her
Si vous mourez tous, il n'y aura plus personne pour le lui dire, n'est-ce pas ?
If you all die, there’ll be no one left to tell him, will there?
— Ne Zha (2019)
I don't dare tell him/her.
Je n'ai pas le courage de le lui dire.
I don't have the courage to tell him/her.
Tu n'aurais pas dû le lui dire.
You shouldn't have told him/her.
When should we tell him?
Je n'ai pas encore réuni le courage de le lui dire.
I haven't yet worked up the courage to tell him/her.
Je n'ai aucune intention de le lui dire.
I have no intention of telling him/her.