Why not iyi?
İyi means good
What's the difference between aşk and sevgi?
it is from arabic origins sevgı is the most general kind of love for exemple foods animal or siblings or a song too but aşk is the love between (the wife <=> husband) (boyfriend <=> girlfriend)
Any adjective besides "nice" would have been more suitable here.
"Love is a very wonderful/beautiful/amazing...feeling".
"Aşk çok güzel bir duygu" = "Love is a very beautiful feeling".