This sentence is from Wang Jide.

The famous saying "Nothing is difficult in the world, only those who are willing" is indeed related to "Mrs. Han's Inscribed Red Note·Private Blessings by Flowers" by Wang Jide of the Ming Dynasty. The more accurate origin should be Chen Yuanliang's "Shi Lin Guang Ji" of the Song Dynasty. It is mentioned in the ninth volume that "nothing is difficult in the world, but the human heart is not firm". It conveys the concept that the difficulty of something does not lie in the thing itself, but in the attitude and determination of the person doing it.

In the process of spreading, it was further refined and popularized, forming the now well-known "Nothing is difficult in the world, only those who are willing".