What do these four words mean when you smile warmly?

There is a saying that a smile makes people warm and reassuring.

Laugh until it is warm, which is a quiet state and a sunny state of mind.

In other words, a warm smile is a kind of mind. I have seen through the so-called bondage and understood the gloom and heaviness of the world, but I still have compassion, face the sunshine, paint a warm luster for the looming hope in the distance, give a warm smile to the passers-by, and write a simple and intimate chapter of truth, goodness and beauty with innocence and spirituality. Xiu Yuan has a long road and never stops.