Prepositions with Clauses
Many Farsi verbs and adjectives are paired with specific prepositions, such as به (to/at), از (from/of), در (in), or روی (on).
When the object of that preposition is a simple noun, it directly follows the preposition. However, when you want to follow the preposition with an entire clause (a full sentence with its own conjugated verb), you cannot attach it directly. You must bridge them using این که (or its connected form اینکه).
You can think of این که as translating to "the fact that."
Pushing for an Action (Subjunctive)
If your main verb expresses a demand or pushes for an action to happen, the verb in the following اینکه clause must be in the subjunctive mood (or use a modal like باید which triggers the subjunctive).
For example, اصرار کردن (to insist) takes the preposition به:
| He insists that we must go tomorrow. | او به اینکه فردا باید برویم اصرار میکند.u be in-ke fardâ bâyad beravim esrâr mikonad. |
Reacting to Facts (Indicative)
If the main verb or adjective describes a reaction to a reality or states a factual observation, the following clause simply uses the normal indicative mood.
Words expressing awareness (آگاه) take the preposition از:
| I am aware that he is not coming today. | من از اینکه او امروز نمیآید آگاه هستم.man az inke u emruz nemi-âyad âgâh hastam. |
Similarly, expressing doubt (تردید) requires the preposition در:
| We have no doubt that they will win. | ما در اینکه آنها پیروز میشوند تردید نداریم.mâ dar inke ânhâ pirooz mishavand tardid nadârim. |
Expressing pride (افتخار کردن) uses به:
| I am proud that I am an Iranian. | من به اینکه یک ایرانی هستم افتخار میکنم.man be inke yek irâni hastam eftekhâr mikonam. |
And showing surprise (تعجب کردن) takes از:
| She is surprised that you have read the letter. | او از اینکه شما نامه را خواندهاید تعجب میکند.u az inke shomâ nâme râ khândeid ta'ajjob mikonad. |
Using روی (On)
This pattern works exactly the same way for verbs that require the preposition روی (on). For example, پافشاری کردن (to stand firm / to persist) requires روی. Because it pushes for a desired action, the connected clause will use the subjunctive mood.
| My brother persists that we must sell the house. | برادر من روی اینکه باید خانه را بفروشیم پافشاری میکند.barâdar-e man ruye in-ke bâyad khâne râ beforushim pâfeshâri mikonad |