Learn Spanish (Spain): El padrino no habría tropezado en el altar. - The best man would not have tripped at the altar.

The perfect conditional (or conditional perfect) is formed using the conditional tense of the auxiliary verb haber (here, habría for the third person singular) followed by the past participle of the main verb, tropezado (from tropezar).

I originally learned that padrino means "godfather." Why is it translated as "best man" here?

In a wedding context in Spain, the padrino is a key figure (often the bride's father or a close relative) who accompanies the bride and acts similarly to the "best man" or "father of the bride." The setting en el altar (at the altar) tells us this is a wedding, shifting the meaning away from "godfather."

Why do we use en for "at the altar" instead of a?

In Spanish, en is the standard preposition for indicating a static location, translating to "in," "on," or "at." The preposition a is primarily used for movement or direction toward a destination. Since the best man tripped while already positioned at the altar, en is required.

Could we place the negative word between the verbs and say "habría no tropezado"?

No, you can never separate the auxiliary verb (haber) and the past participle (tropezado) in Spanish compound tenses. Negative words like no, as well as any object pronouns, must always be placed directly before the conjugated form of haber.