換了一顆心此情不換o亂了一段情此心不亂o
[huàn le yī kē xīn cĭ qíng bù huàn o luàn le yī duàn qíng cĭ xīn bù luàn o]
‘Changed heart, yet this feeling never fades away; confused this love but remains true.' It means despite changing circumstances, even changes in life like exchanging hearts (metaphor for deep transformation), some feelings will still remain constant and steadfast, highlighting a loyal and unchanging love.