1. brighten; flood with light
1. Electricity made it possible to illuminate city streets to a degree previously unimaginable.
2. clear up; make understandable; explain
2. He is a gifted speaker, and is able to illuminate any issue he talks about.
in (into, in, on, upon)#lumen luminis (light) (Latin)
when divided sounds like I+ll (will. i'll)+luminate. (means. shine light on something, make a way clear for somebody. ). so you have decided to clear the way for your friend, which shows your understanding with him.