Learn Spanish (Latin America): Mi fe es inquebrantable, pase lo que pase. - My faith is unwavering, whatever happens.

This is a reduplicative subjunctive clause, which is used to express indifference or that a situation will remain true no matter the circumstances. It repeats the present subjunctive of the verb pasar (to happen) around lo que (that which). The structure [subjunctive] + lo que + [subjunctive] is the standard way to say "whatever [verb]s."

Could I use the indicative here and say pasa lo que pasa?

No, because that changes the meaning entirely. Using the indicative pasa lo que pasa translates to a concrete statement of fact, like "what happens, happens" or "this is what happens." To express the hypothetical idea of "whatever might happen in the future," you must use the subjunctive form pase.

Can I use this same repeating structure with other verbs?

Yes, it is a very common pattern! You can use it with many verbs to express "no matter what..." For example, cueste lo que cueste (whatever it costs), digan lo que digan (whatever they say), or hagas lo que hagas (whatever you do). Just remember to put the verb in the subjunctive both times.

How is the word inquebrantable constructed?

It is built from the verb quebrantar (to break, smash, or violate). By adding the negative prefix in- (un-) and the suffix -able (-able), you get a word that literally means "unbreakable." When talking about abstract concepts like faith, loyalty, or spirit, it is usually translated as "unwavering" or "unshakable."