There is of course never a guarantee, but scoring in the 80s consistently is a good indicator of readiness. After all... I always tell my students that if they consistently score >80% on questions that they have never seen before then they can consider taking the exam.
So if you score in the 80s the first time you take exams then that's a good sign.
Training for Project Management Professional (PMP)®, PMI Agile Certified Practitioner (PMI-ACP)®, and Certified Associate in Project Management (CAPM)®