When it comes to being confident or sure about something, there are many different synonyms that can be used to convey the same message. Some alternatives to the phrase "wert sure about" might include "were certain," "had no doubt," "were convinced," "had faith," "were confident," "had no reservations," "knew for certain," or "had complete trust." Depending on the specific context and tone of a conversation or piece of writing, different synonyms may be more appropriate or effective than others. Ultimately, the goal is to convey a sense of steadfast belief or certainty, regardless of the specific phrasing used to do so.