The phrase "opened heart" can be synonymous with many other phrases and words that convey the same sentiment. These could include "vulnerable," "transparent," "authentic," "sincere," and "honest." Other synonyms may include "unguarded," "frank," "forthright," "guileless," and "candid." All of these phrases denote a willingness to be open and honest with others, to be understanding and empathetic, and to share oneself with others. It takes a lot of courage to show vulnerability and open oneself up to the world, but it is often essential for building genuine connections and relationships with others.