Synonyms for Blurt out:

n.

exclaim, gush, burst out with, tell, divulge, utter. blurt out (noun)
blurt, blunder out.

v.

betray (verb)
tell.
blab (verb)
divulge.

Other synonyms:

tell. cry out
exclaim.
Other relevant words:
exclaim, utter, burst out with, divulge, tell.