If I were to... I would...

Question

Hello, I was wondering if for sentences like "if she were to..., she would...," we use the tense imparfait and conditionnel présent? I also saw sentences that use the verb devoir "si elle devait faire cela..." in these kinds of sentences. Is that correct?

Answer

You are on the right track. Link below:
l-imparfait-usage-in-hypothetical-clauses-introduced-by-si-if-followed-by-le-conditionnel-present

Answer

Hypothetical clauses work pretty much the same in English and French. You need to break them down in to 2 parts: the if-part (subordinate clause) and the main part (main clause). Just as in English, the conditional (if there is one) never goes into the if-part.

There are three stages of likelihood, each associated with the proper tense in each part:

If your are nice, I (will) come with you. -- Si tu es gentil, je t'accompagne (accompagnerai).
If you were nice, I would come with you. -- Si tu étais gentil, je t'accompagnerais.
If you had been nice, I would have come with you. -- Si tu avais été gentil, je t'aurais accompagné.

The verb devoir is no exception.