According to a verse in the Quran: "They will not hear therein any vain or sinful talk, only the words of peace and tranquillity." (56:25-26)
There are three terms which explain the character of people of Paradise: La yasma'una fiha laghwan wala tathima, illa qeelan salaman salama. That is, in Paradise people will not hear any vain or sinful talk, only words of peace. There are two things here: nuisance and sinful talk. Paradise will neither have nuisance nor any sinful talk. There will only be complete peace. This does not mean that the people of Paradise will constantly be greeting one another with 'Assalamu alaykum'. Rather, it means that people of Paradise will have peace in their hearts for one another. This is about an inner spirit, and not any kind of lip service. The verse does not mean that the people of Paradise will constantly be greeting one another with 'Assalamu alaykum'. If this happens, there will be a lot of noise in Paradise. Life will become a problem. People of Paradise will have complete peace in their hearts and minds for others. That is, they will become completely peaceful individuals for others. If you think, the criterion is that you must live in Paradise as a peaceful person. This means it is very important to have a peaceful character, to be serious and sincere, and to have well-wishing for others. All these qualities will result naturally if you reflect on this matter. No person will experience nuisance in Paradise. There will be no noise. People will not indulge in sinful talk against others. They will have peace for all. Every individual has to develop such a personality. Only such a personality will find entry to Paradise.