The spelling of the name "Kirstina" can be explained using IPA phonetic transcription. The initial sound is /k/, followed by the vowel sound /ɜːr/. The next sound is a consonant blend of /st/. Then, the vowel sound /i/ is followed by the consonant sound /n/. Finally, the last sound is the vowel sound /ə/. Therefore, the correct spelling of this name is "Kirstina" and it accurately reflects the pronunciation of the name.