Jinās involves similarity of sound or form between words whose meanings differ. Sajʿ is patterned sound correspondence at the ends of prose clauses. The first depends on lexical resemblance with semantic difference; the second on end-position cadence.
A passage can exhibit both effects if similar words also conclude successive clauses. But rhyme alone does not establish jinās, and similar words anywhere in a paragraph do not establish sajʿ. Check both the words' meanings and their positions.