Questions & Answers about Kvinnan var övertygad om att ryktet stämde.
Why is stämde in the past tense here? What if the rumor is still true today?
This is an example of backshifting. Because the main clause is in the past tense (Kvinnan var), the verb in the indirect speech clause (att ryktet stämde) must also shift to the past tense to match it. Even if the rumor is still true right now, Swedish (like English) shifts the tense back because the main reporting verb is in the past.
Why is om included before att? The English translation just says "convinced that".
In Swedish, certain adjectives and verbs are strongly linked to specific prepositions. Övertygad (convinced) pairs with om (of/about). When you add a clause starting with att (that), you do not drop the preposition. The combination övertygad om att literally translates to "convinced of [the fact] that".
Could I say att ryktet var sant instead of att ryktet stämde?
Yes, att ryktet var sant works perfectly and means the same thing. However, using the verb stämma (to be correct or to add up) is extremely common in Swedish and sounds very natural when talking about whether facts, statements, or rumors are true.
Why does övertygad end in -d?