The France midfielder was linked with an exit during the summer and rumours have persisted throughout the early weeks of the season about a possible exit.
"In this moment I'm completely in the dark," Mourinho said. "The only thing that is clear for me is that the player never, never in all these days we are together, told me he wants to leave. Paul came back after the World Cup in the week before the start of the Premier League so we have been together for about two months or so and he has never told me that he wants to leave."
The United manager was also asked whether he believes Mino Raiola, Pogba's agent, was seeking to construct a way out of Old Trafford for his client. "I don't know if that is true," Mourinho said. "I need the agent to tell you (the media) in a way that I can see."
James Robson of the Evening Standard relayed quotes from the former Juventus man given earlier in September that cast further doubts over his loyalty to United:
Prior to the end of the European transfer window, it was reported by Chris Wheeler of the Daily Mail that Pogba wanted to move to Barcelona. It was also stated by Tuttosport (h/t journalist Arjun Pradeep) that the 25-year-old would like to link up with Cristiano Ronaldo at Juventus.
If Mourinho is indeed "in the dark" when it comes to Pogba's position at the club, then it's not an ideal situation for United in what's been a testing spell.
The team suffered disappointing back-to-back losses in the Premier League against Brighton & Hove Albion and Tottenham Hotspur earlier in the campaign. Despite a 2-0 win at Burnley before the international break, the Red Devils appear a long way behind the likes of Manchester City, Liverpool and Chelsea.
Pogba has scored twice already this term, although his performances have been a little hit-and-miss so far in 2018-19 for club and country.
Miguel Delaney of The Independent said he wants to see a little more from the midfielder:
After the international break, all eyes will be on United's No. 6 when he takes to the field at Vicarage Road on Saturday evening.
Following Watford's perfect start to the season, the match will be a challenge for the Red Devils in what promises to be a hostile atmosphere. Mourinho will want to see his big players, including Pogba, make their mark.