Hi If I need money from a guy in UAE. But I have...

You must check with the police station to open a complaint against the debtor provided that you provide the document that proves the validity of your complaint and you can accuse this person of fraud and the police will track and arrest the debtor and bring him to court on charges of fraud or other charges may vary according to the document that proves the complaint is valid.
Here is the text of the UAE Penal Code related to your inquiry:
Article 399 :
Shall be punishable by confinement or by a fine any individual who, by using fraudulent practice, assuming a false name or quality, takes possession for himself or for the others of any movable property or written instrument, or obtains any signature upon such instrument, its cancellation, destruction or amendment, whenever it is intended to deceive the victim and bring him to surrender a legal right. Shall also be liable to the same punishment he who alienates an estate or a movable property while being fully aware that it is not his own or that he has no right to dispose thereof; or he who knowing by alienates any of the above mentioned after having previously disposed thereof or having concluded any agreement thereon, whenever such an act operates to the injury of others.If the object of crime is a property or an instrument pertaining to the State or to any of the authorities mentioned in Article (5) above, this shall be considered a circumstance of aggravation.Attempt shall be punished with confinement for a period not exceeding two years of with a fine not exceeding twenty thousand Dirhams. And where a recidivist is convicted and sentenced to confinement for a period of one year or more, the Judge may order that he be put under police surveillance for a period neither to exceed two years nor to exceed the duration of the inflicted penalty

The assessment of the strength of the criminal evidence for the commission of the crime depends on the discretion of the judge