On March 12, Sunmi appeared as a guest on KBS2's 'Yoo Hee Yeol's Sketchbook' to introduce viewers to her latest comeback single, "Tail"!

In addition to delivering an enticing performance of her title track, Sunmi also performed b-side track "What The Flower", showcasing her talents as a versatile singer, song-writer, and dancer. 

During her interview portion, Sunmi got honest about her personal struggles, both as a member of Wonder Girls and on her own. First, the solo artist reflected on her Wonder Girls days. "Back then, I did not shine in any area, whether it was dance, singing, or visuals. I couldn't shine anywhere. I felt so depressed back then. I thought, 'I work just as hard, why can't I shine on stage?'. I was 16-years old, but I spent my youth living inside a moving vehicle. All I did was catch up on sleep while moving from schedule to schedule. I had no idea who I was in my youth. I had no time to even consider myself. Afterward, I was really sick. So when I took a break, I worked hard to ask myself, 'Who am I'. I learned that I was someone who wanted to be loved by others, someone who is scared of being cast off." 

Next, Sunmi opened up about an unreleased song, with lyrics completely in English! She said, "In the past, I was diagnosed with borderline personality disorder. It is a disorder where you become one person on moment, then a completely different person the next. I'm much better now, and I can have regular conversations with people. I do not consider it a shortcoming of myself any more. I once wrote a song about it, but when I wrote the lyrics in Korean, it seemed too literal. So I wrote English lyrics, and that song is 'Borderline'." 

Listen to a snippet of Sunmi's "Borderline" above, and check out more clips from her 'Sketchbook' appearance this week, below!