How do you say " No, I don't have a boyfriend" in Korean? :D
If you could put the phonetic pronunciation also I would be very happy.

Question

Answer

I'm not a native Korean speaker (I'm sorry ㅠㅠ) but when my Korean friends ask me I say:

아니요, 남자친구 없어요.
(Ah-ni-yo, nam-ja chin-gu ob-seo-yo)
or
아니, 남자친구 없어.
(Ah-ni, nam-ja chin-gu ob-seo)

One is in 반말 (informal; the bottom one) while the other is in 존댓말 (formal).

Answer

Using the informal and casual speech, it would be:

아니, 난 남자친구(가) 없어.  (아니: No, 난: I, 남자친구: boyfriend, 없어: do not have)

"Ah'nee ^^ nahn ^ nam'ja chin'gu up'seo"  (^ indicates a short pause)
Or "Ah'nee ^^ nahn ^ nam'ja chin'gu'gah up'seo".