As a verb, there are only two sounds, re and sume, and the stress is on the second syllable: ri 'zju: m.

There are three sounds when you are a noun, re, su, me, and the stress is on the first syllable:

Resume is a noun. When you say a resume, the pronunciation is similar to "re z (inverted e)mi", in which the "e" of "re" is still pronounced with the vowel e.