It's Lin Na's song "Mood is as Happy as the Warm Sun", complete lyrics:

I can't help but want to hum it.

Joy flows in my heart.

Happiness overflows on the face.

My mood is as bright as the sun.

The sweetness of love ripples in my heart.

The mood is particularly joyful.

Like the warm sun.

As bright as the sun.

I can’t help but want to hum.

Joy flows in my heart.

Happiness overflows on the face.

My mood is as bright as the sun.

I can’t help but want to hum. ?

Joy flows in my heart.

Happiness overflows on the face.

My mood is as bright as the sun.

The sweetness of love ripples in my heart.

The mood is particularly joyful.

Like the warm sun.

As bright as the sun.

I can’t help but want to hum.

Joy flows in my heart.

Happiness overflows on the face.

My mood is as bright as the sun.

The sweetness of love ripples in my heart.

The mood is particularly joyful.

Like the warm sun.

As bright as the sun.

I can’t help but want to hum.

Joy flows in my heart.

Happiness overflows on the face.

My mood is as bright as the sun.

Lin Na's singer profile:

Lin Na, a mainland music composer and singer, participated in many online original pop music song and song competitions during her schooling. She continued to practice in the competitions and won the Having passed the second prize, two digital music albums have been released, namely "Girl" and "Take You There". Its main representative works include: "The Age of Dreaming", "Surrounded", "Perseverance" "etc.