hacérselo

to do it to/for him, her, or them, to make him, or them understand it

→ hacer
hacér to do, to make + se if + lo Third-person singular direct object
verb Rare #52,296
to do it to/for him, her, or them The pronoun se can refer to one person or multiple people; context determines who.
SP: Voy a hacérselo mañana.
EN: I'm going to do it for them tomorrow.
to make him, her, or them understand it In this construction, hacérselo entender means “to make someone understand it.”
SP: Quiero hacérselo entender con calma.
EN: I want to make them understand it calmly.
Conjugation of hacer
Indicative present
SingularPlural
First hago hacemos
Second haces —
Third hace hacen
Subjunctive present
SingularPlural
First hago hacemos
Second haces —
Third hace hacen
Indicative past
SingularPlural
First hice hicimos
Second hiciste —
Third hizo hicieron
Imperative
SingularPlural
First — hagamos
Second haz háganlo
Third haga hagan
Indicative future
SingularPlural
First haré haremos
Second harás —
Third hará harán
Subjunctive future
SingularPlural
First haré haremos
Second harás —
Third hará harán
Present
Conditional
SingularPlural
First haría haríamos
Second harías —
Third haría harían
Indicative imperfect
SingularPlural
First hacía hacíamos
Second hacías —
Third hacía hacían
Subjunctive imperfect
SingularPlural
First hacía hiciéramos
Second hacías —
Third hacía hacían
Past
Subjunctive
SingularPlural
Second hagas —
Subjunctive past
SingularPlural
Third — hicieran

Tengo que hacérselo entender.

I have to make him understand.

— Cinema Paradiso (1988)

Debes hacérselo.

You should do it.

¿Por qué tenían que hacérselo a ellos?

Why did they have to do that to them?

— Кин-дза-дза! (1986)

¿Quieres hacérselo?

Do you want to do it to him?

— Paris, je t'aime (2006)