Is It More Likely or Most Likely?

"More likely" is a phrase which is often translated as "más probable", and "most likely" is an adjective which is also often translated as "más probable".

Is more likely grammatically correct?

In this case "more likely" relates to greater while "most likely" relates to greatest. Because "more" is used when comparing two people, you would say: Janus is more likely to commit crime than Mike because Janus has a history of mania.

What is the difference between more likely and most likely?

Most likely expresses what particular action/event has the biggest chance to occur out of several different possibilities. More likely compares different actions/events to see which one has a greater chance to occur than another.