I've heard this song on the radio a lot here in Korea and immediately recognized the melody from jpop duo Capsule's "STARRY SKY." Whether it was sampled with permission or not I don't know, but this could be a case of a plagiarism that hasn't seen the light of day yet. The part in question is at 3:09.
Listen from 2:02. That sampling is unmistakable.
I went ahead and contacted both groups via their contact boxes and fbs. Hopefully it's just sampling with permission.
Sources: ktmusic, ludacris28