Assumption College in Worcester is promising not to raise tuition for next fall’s incoming freshmen during their four years at the school. The Assumption Assurance program was announced Sunday by the college’s president, Francesco Cesareo. Current freshmen and sophomores will also have their tuition frozen at the 2014-15 rates for the balance of their time at the school. Next year’s tuition is expected to be more than $35,500. Assumption officials said the program is about taking some of the uncertainty out of budgeting for a four-year education and that it could potentially save students and their families thousands of dollars.