What is the ruling on the prayer of one who felt urine being discharged during it but found no trace of it after the prayer, and is he required to repeat it? And what are the things that help one avoid showing off?

If you doubt that urine was discharged during prayer, and you do not find any trace of it after prayer, then your prayer is valid. This is because the original state is the continuation of purity until something that nullifies it is proven. Whoever is certain of purity and doubts the occurrence of an impurity should base their action on the certainty of purity, and ablution is not obligatory for them, whether the doubt occurs during prayer or outside of it. This is based on the saying of the Prophet, peace and blessings be upon him: "He should not leave (his prayer) until he hears a sound or finds a smell."