is it true unmarried people are inferior? there some people who died unmarried, will allah look down on them? is marriage a must to enter jannah?

All perfect praise be to Allah, The Lord of the Worlds, and peace and blessing be upon the Messenger of Allah, his family, and all his companions.

People’s degrees with Allah the Almighty vary according to their righteousness, not marriage, and as far as we know, Sharee’ah has never considered marriage a measure for superiority. However, there are some Hadeeths, that scholars have differed regarding their authenticity, which indicate that marriage is half of the religion, such as the hadith “Whomever Allah blesses with a righteous wife, He has helped him with half of his religion, so let him fear Allah with regard to the other half.” Narrated by At-Tabarani in Al-Awsat and Al-Hakim attributed to Al-Bayhaqi. Al-Haakim graded its chain of narration as Saheeh (sound)]. In the narration by Al-Bayhaqi, the Prophet, sallallaahu`alayhi wa sallam, said, “If a man is married, he has indeed completed half of his religion, so let him fear Allah in the other half.” [Al-Albaani graded it Saheeh (sound) in Saheeh at-Targheeb wat-Tarheeb]

Al-Qurtubi said in his Quran interpretation: "Whoever gets married has completed half of the religion, let him fear Allah for the second half." That means marriage leads to chastity and protects from fornication. The chastity is one of the two traits upon which the Messenger of Allah, sallallahu ‘alayhi wa sallam, guaranteed Paradise for whoever maintains them. He, sallallahu ‘alayhi wa sallam, said: "For whomever Allah protects against the evil of what is between his jaws and the evil of what is between his legs, he shall enter Paradise." [Al-Muwatta and others].

As marriage protects from fornication and preserves the chastity, while chastity is one of the two traits, but it does not necessitate that the married person is in a higher degree with Allah than the single. How many married people who lack piety, failed to be chaste, and committed fornication! And how many very pious unmarried people protected stood clear from fornication, also how many married people were unable to preserve the other trait, so failed to preserve the limits of Allah regarding their tongues and food, and how many unmarried succeeded in preserving them.

Allah knows best.