I want to travel to Curitiba
I want is it safe or no
As it stated in the MonteCD link about safety in Curitiba, "Curitiba in general is considered as a fairly safe Brazilian city for visitors." To come to Curitiba as tourist is quite different from settling down here. Most people who intend to move to Curitiba is lured by what the city used to be - good means of transport, safety, clean streets, in short good quality of life. Unfortunately things are rather different now, as tourist is a nice place to visit, to settle down, well it depends of your standards and what you looking for.
TripAdvisor is not the best place for the answers you are aiming at - TA main focus is for travelers as tourists.