Learn Arabic (Modern Standard): سوف أستقر في المدينة حيث يعمل أخي. - I will settle down in the city where my brother works.

You would replace the future marker سوف with عسى أن. Because the particle أن forces the following verb into the subjunctive mood, the final vowel on the verb changes from a damma (u) to a fatha (a). The sentence becomes: عسى أن أستقرَّ في المدينة حيث يعمل أخي.

Why is 'where' translated as حيث here instead of أين?

أين is strictly a question word used to ask 'where?' in interrogative sentences. حيث, on the other hand, is an adverb of place used to link two clauses together. Since you are referring to 'the place where' an action happens rather than asking a question, you must use حيث.

What is the root of the verb أستقر (I settle down), and why does it end with a shadda?

The verb comes from the root ق - ر - ر. Because the second and third root letters are identical, they merge together and take a shadda (a doubling mark). This specific verb is in Form X (Form 10), which is created by adding the prefix استـ to the root.

Can I attach the future prefix سـ instead of using the separate word سوف?

Yes, you can say سأستقر instead of سوف أستقر. Both express the future tense. While سوف is traditionally used to imply a slightly more distant future than سـ, in modern written Arabic they are largely used interchangeably.