j'en serai

I will be

→ je
phrase Rare #35,821
I will be Used with être in the future tense; en usually refers to something previously mentioned, meaning “of it,” “about it,” or “in it,” depending on context.
FR: J'en serai très fier.
EN: I'll be very proud of it.

J'en serai enchantée, monsieur.

I would be delighted, sir.

— Harry Potter et le Prince de sang-mêlé (2009)

On le fera voler cet été et j'en serai le pilote.

We'll fly it this summer, and I'll be the pilot.

— Kiki la petite sorcière (1989)

J'en serai ravie.

I would be delighted.

J'en serai heureux.

I will be happy.

J'en serai toujours capable?

Will I always be able to do it?

J'en serai honoré.

I would be honored.

J'en serai ravi.

I will be delighted.