ellos alegrarán

will cheer up, will make happy, will be happy, will be glad

→ alegrar
alegr to cheer up, to make happy, to gladden + arán 3rd-person plural future
verb · 3rd-person plural, future tense Rare #51,632
will cheer up, will make happy With se, alegrarse means “to be happy” or “to be glad.”
SP: Tus flores alegrarán la habitación.
EN: Your flowers will brighten the room.
will be happy, will be glad This is the pronominal form alegrarse.
SP: Se alegrarán cuando llegues.
EN: They'll be glad when you arrive.
Conjugation of alegrar
Indicative future
SingularPlural
Third alegrará alegrarán
Subjunctive future
SingularPlural
Third alegrará alegrarán

Algunas personas se alegrarán de que no esté.

Some people will be glad that I'm not there.

— Vivir (1952)

Se alegrarán mucho.

They will be very happy.

— Zárójelentés (2020)

Ellos se alegrarán mucho.

They will be very happy.

Las flores alegrarán la mesa.

The flowers will brighten up the table.