St. Xavier's University,Kolkata is one of the most reputed universities across India. There are various Entrance tests conducted for admission in various UG and PG courses. It definately has more difficulty level in the exams however it all depdends on you and your capability.
I suggest you to check out the previous years papers and practice them to get an idea.
You can find more here: https://www.careers360.com/university/st-xaviers-university-kolkata
Hope it helps.