Hi Mary,
The way to pronounce the word ‘Suir’ is Sure as in being positive. Hope this is of some help. If you want any other information just send me an e mail

Regards, Phil

Phil– Thanks so much!! For “sure” you are a great guy! 🙂

S is only pronounced sh in Irish if it precedes e or i, otherwise it is Sssss. Think of the names Seán and Síle (Shawn and Sheela).  The river’s name is much closer to the English sewer than to sure.