On this week's episode:

1. Something does not exist where it should

Falta seguridad en este barrio.

There is a lack of security in this neighborhood.

I am $3 short of buying the book I need.

Me faltan 3 dólares para comprar el libro que necesito

1. To miss an important obligation

Hoy falté a la escuela

I missed school today

1. When something is missing from where it usually is

Me falta un libro en el estante

I'm missing a book on the shelf

1. Failure to fulfil a promise or complete what is expected

He promised to call me yesterday, but he broke his word.

Me prometió que me llamaría ayer, pero faltó a su palabra.

1. When something could improve something else if it was there

The soup is lacking salt (to the soup salt is missing).

A la sopa le falta sal.

HACER FALTA

1. hacer falta = to be necessary

a. Para dominar un arte, hace falta esfuerzo y dedicación.

To master an art, hard work and dedication are needed/necessary.