It signifies that life is always viewed from a good perspective, that despite the negativities one has experienced, one still does not lose hope, and that even evil is responded to with good. Smiling is also an expression of people who are happy with their lives and appreciate what they have. It is also called a good heart and magnanimity.
It symbolizes people who are extroverted, unable to keep secrets, approach people disinterestedly, and have a pure, childlike side. It also states that the dreamer is attached to people immediately after the relationships he establishes with them, and that he always wants to stay close to the people he loves.