If we could put a man on the moon in the 1960’s we will find a way to put a man on Mars today especially given that we’ve already successfully landed multiple rovers and landers on the planet. Yes it is difficult, as with the Apollo missions new technologies will need to be developed and there will be risks but it can be done if we as a nation decide to do it. Unlike visiting our nearest star there is no specific technological limitation that prevents us from colonizing Mars.
Another frequent question is whether or not anyone would be willing to go and live out their remaining lives on Mars. As Mars One has proved, there is no shortage of people willing to do this especially if it is well planned and there is a strategy in place to keep them well supplied and safe long term. While a lot of people could not imagine why you would want to give up your life on Earth to live on a desolate planet, there are many people out there who crave adventure and the unknown, even knowing they are unlikely to ever return to Earth, as they know they would go down in history as the first pioneers to colonize another planet and would be contributing to a cause greater than themselves.