insistir en que

Question

Hola Foro y los expertosTengo una pregunta a propósito de la part de la oración  'pero he de insistir en que vayas a Córdoba'. Por qué, usamos 'en' aquí.  No es  possible decirlo igualmente sin 'en', 'pero he de insistir que vayas a Córdoba'.

Answer

Hola Paris,
To say "to insist that..." in Spanish we use "insistir en que + subordinate clause". It is incorrect to omit the "en" and just say "insisto que...". However this is a common mistake that is often seen even in newspapers. Here is an article talking about this. Have a look.
Inma

Answer

Paris - It is not really feasible to formulate an all-embracing rule to guide us as to what preposition has to follow each Spanish verb - they just have to be learned. A useful publication is "Diccionario de Uso de las Preposiciones españolas" by Emile Slager and Manuel Seco [Espasa Calpe]; nouns are included as well as verbs. Often, different prepositions can be chosen depending on the context. The book gives numerous examples from Spanish books and magazines.

Indeed, it is the same in English - where [just like in Spanish] learning and choosing the correct preposition is not at all a straightforward task, such that mistakes are quite common.