Learn Swedish: Det finns en viss risk. - There is a certain risk.

In Swedish, det finns (literally 'it exists') is used to say that something exists or is available, just like 'there is' or 'there are' in English. You use det är when describing what a specific thing is, like saying 'it is a risk' (det är en risk), rather than stating the general fact that a risk exists.

I thought viss meant 'sure' or 'confident'. Does it mean the same thing here?

It translates to 'certain' in both English senses! While it can mean being sure about something, in this sentence it acts just like the English phrase 'a certain' to mean 'a particular' or 'some amount of', as in 'a certain risk'.

How does the adjective viss change if I use it with different words?

Because risk is an en-word, we use the base form viss. If you were describing an ett-word, like problem, it would become ett visst problem (a certain problem). For plurals, you use vissa, such as vissa risker (certain risks).

Can I change the word order if I want to put more focus on the risk?

Yes! If you want to emphasize the risk itself, you can move that phrase to the front of the sentence: En viss risk finns det. Notice how the verb finns must stay in the second position, which pushes the subject det to the other side of the verb.