The negative present tense is the only tense where 'a' changes in 'i'. For all other tenses the stem remains unchanged. Verbs of Arabic origin also keep their original vowel (usually not an 'a') in the present negative tense: e.g. sijaribu = I don't try,
I guess that would mean "I will not be lost", as in, no one will lose me.
If a ball could think, a ball would think "sitapotezwa" when it is convinced its owner will never lose it. The owner will say "sitapoteza mpira", "I will not lose the ball".