Paul Pogba said he needs to be happy to perform at his best for Manchester United, adding that he would be fined if he spoke his true feelings.
The midfielder, 25, won the World Cup with France in the summer and scored in United’s 2-1 win over Leicester in Friday’s Premier League opener.
But Pogba fell out of favour during the 2017-18 campaign and this summer he was linked with a move to Barcelona.
“If you’re not happy, you cannot give your best,” Pogba said.
“There are things I cannot say otherwise I will get fined,” he added.
Asked about the differences between playing for France and playing for United, Pogba said: “I am the same, but it’s a different team, obviously.
“I still enjoying playing football but like I said, when you are comfortable or confident and are good in the head, it’s going to be easier.”
Pogba, who wore the captain’s armband for United on Friday, added: “I always love the club [United]. I came from the academy, I played for the first team. For me, it was a dream come true.”
Pogba scored as France beat Croatia 4-2 in the final to win the World Cup in July for the second time.
After France’s victory, former United defender Rio Ferdinand said it was “down to Jose [Mourinho] to unlock this Pogba we saw at the World Cup because he was responsible, he stood up to a lot of hard tests in midfield, and was a talisman for this team”.
United manager Mourinho praised Pogba for being “absolutely brilliant” in Les Bleus’ final three matches in Russia.