The phrase "more sure thing" expresses a high level of certainty or confidence about a particular outcome or decision. Synonyms for this phrase may include "more certain," "more reliable," "more assured," "more confident," "more guaranteed," or "more definite." These words convey a sense of trust and dependability, indicating a strong belief that something will happen or be successful. Using these synonyms in place of "more sure thing" can add variety to language and help avoid repetitive phrases. Ultimately, the choice of synonym depends on the context and tone of the message being conveyed.