Sunderland manager Martin O'Neill does not believe Stephane Sessegnon could perform so well for the club if he was unhappy on Wearside.
Sessegnon joined the Black Cats from Paris St Germain in January 2011 and he has scored seven goals in the Premier League this season.
However, there have been suggestions that the Benin international's family is homesick and he has been linked with a return to PSG.
Arsenal have also been credited with an interest in the attacker, who has played an instrumental role in Sunderland's revival under O'Neill.
The Black Cats chief does not expect speculation about Sessegnon's future to stop, but he is confident there are no major issues troubling the 27-year-old.
"There's talk about Sess being unhappy and that he's having a tough time with his family but, believe me, he couldn't be happier," said O'Neill.
"I'm sure it won't stop the speculation but I don't think he could play like he has been if he was unhappy.
"He's been brilliant for us and we want to keep him here."