How to know if a job offer is real or scam in the UAE

Hi Madam,

My name is K B.

My wife attended an interview last Friday in an office in Business Bay, Dubai. She got selected and they said will release the offer letter on Sunday.

When I tried to search for the company information, I dint not find any results. Also, the employer responds only on Whatsapp at night at 1:45 AM. So I am a bit worried if it is a valid company.

Please advise