I'm not such expert in this field but I'll try my best to answer.
Well it's pretty hard to differentiate between both of them but one can find the answer.
Crush doesn't last for long time . If you like someone and loose intrest in him/her after a couple of weeks or months the it's a crush for sure . If it last longer say abt 6 months or seven months then it's true love .
Also when u love someone u can't stop thinkin abt him/her which is not in the case of crush .Crush is mainly bcoz of how the person looks .
While true love is only when u like a person not considering the looks . Looks are also important but his/her qualities matter more than looks
I hope I answered it good
