Correct spelling for the English word "Achievance" is [ɐt͡ʃˈiːvəns], [ɐtʃˈiːvəns], [ɐ_tʃ_ˈiː_v_ə_n_s] (IPA phonetic alphabet).
Performance.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.