The lyrics of Jin's "Heart on the Window" (featuring Wendy) evoke a feeling of longing, devotion, and the enduring nature of love despite time and distance. The "heart on the window" serves as a powerful metaphor. Let's break down the likely thoughts and background:

• The Metaphor of the Heart on the Window: The central image is a heart drawn on a window, presumably with condensation or frost. This is a delicate, ephemeral image – easily wiped away, yet deeply meaningful. It represents the singer's feelings, vulnerable and exposed, yet clearly visible to the beloved. The act of drawing the heart is a silent declaration of love, a testament to enduring feelings that transcend the physical separation. The "window" itself might symbolize a barrier – distance, time, or even unspoken words – but the heart transcends this barrier.

• The Passage of Time ("숱한 계절들을 넘어"): The lyrics emphasize the passage of seasons and time ("many seasons have passed"). This highlights the longevity of the singer's love, suggesting it's not fleeting but deeply rooted. The breath ("입김") that creates the heart on the window further reinforces this idea of time passing and the persistent nature of the emotion.

• Longing and Anticipation ("널 기다린 시간 너머"): The lyrics speak of waiting ("the time I waited for you"), suggesting a period of separation or longing. The "waiting" emphasizes the depth of the feeling and reinforces the sincerity of the declaration of love.

• Vulnerability and Exposure: The act of drawing a heart on the window is inherently vulnerable. It’s a public display of emotion, leaving the singer exposed. This showcases the sincerity and strength of the singer's feelings.

• Wendy's Verse: Wendy's verse adds a complementary perspective. Her lines suggest that the love has brought light ("빛으로 가득 채워") into her previously dark heart, showcasing a reciprocal and transformative relationship.

• Overall Theme: The song is about unwavering love and devotion, despite distance and the passage of time. The "heart on the window" is a symbol of the singer's persistent feelings, visible and vulnerable, a testament to the power of love's enduring nature. The song's overall tone is romantic, heartfelt, and hopeful. The repeated "I'll love you better" in the bridge reinforces this promise of commitment and deepened affection.

In short, the song likely stems from a place of deep affection and longing, using the image of a heart on a frosty window to express the vulnerability, persistence, and beauty of a lasting love. The collaboration with Wendy adds a layer of shared experience and mutual devotion.