According to Evening Standard, Mourinho assured Sanchez that he will be the star man in his squad at the Theatre of Dreams.
It has been revealed that the reported promise by Mourinho made Sanchez to leave the Gunners for Old Trafford.
Sanchez joined the Red Devils in a player-swap deal that saw Henrikh Mkhitaryan join Arsenal, Naija News recalls.
The 29-year-old earns around £400,000-a-week at United but has just netted four goals and has been dropped by manager, Jose Mourinho in recent weeks.
Meanwhile, United is open to selling Sanchez during the January transfer window, should the forward decided to leave Old Trafford.
Source: Naija News