Kobato.

Sweet and naïve Hanato Kobato has come to Earth on a mission to collect and fill a bottle with "konpeito," which appears after healing a person's heart that is suffering. Kobato collects these because it is her wish to go to a certain place. Despite her strangeness, Kobato turns out to be well-suited for this mission as her heartfelt sincerity in helping others earns her the love and admiration of everyone she meets; however, she is not allowed to fall in love with anyone whose heart she heals.