Impassioned comes from the Latin word passionem, meaning "suffering or enduring," and originally referred to the suffering of Christ on the cross, known as "The Passion." In other words, impassioned had a sense of trauma and anguish associated with it and only later did it come to describe happier feelings as well. Whatever the emotional feeling behind impassioned, it's still a word that suggests profound feeling and sincerity on behalf of the user.