-- Tannisho, Chapter III
But the people of the world constantly say, even the evil person attains birth, how much more so the good person. Although this appears to be sound at first glance, it goes against the intention of the Primal Vow of Other Power. The reason is that since the person of selfpower, being conscious of doing good, lacks the thought of entrusting the self completely to Other Power, he or she is not the focus of the Primal Vow of Amida. But when self-power is turned over and entrusting to Other Power occurs, the person attains birth in the land of True Fulfillment.
The Primal Vow was established out of deep compassion for us who cannot become freed from the bondage of birth-and-death through any religious practice, due to the abundance of blind passion. Since its basic intention is to effect the enlightenment of such an evil one, the evil person who is led to true entrusting by Other Power is the person who attains birth in the Pure Land. Thus, even the good person attains birth, how much more so the evil person!
All that the evil person needs to do is to turn about and cross over to the bodhisattva path, repenting of his evil ways.
Within context of Jodo Shinshu, evil refers to a person's motivation to do good with thought of fame and reward. Such moral calculations usually end up as one's stumbling block since such high expectations lead one to be dissatisfied the results of one's good actions.
For no good deed goes unpunished! :p
Yet those evil people who repent of their evil and follow the Buddhadharma are praised for changing their ways.
Even so, no one in this life can say for certain if a person will be reborn in the Pure Land. All one can do is have faith that one will be reborn in the Pure Land.
Tannishp chapters I to X: http://www.livingdharma.org/Tannisho/TannishoChaptersI-X.html
Primal Vow: http://en.wikipedia.org/wiki/Primal_Vow