Antonio Conte feels his friendship with agent Jorge Mendes and Diego Costa's commitment to Chelsea will ensure the striker remains at Stamford Bridge.
The Spain international is, alongside the likes of Cristiano Ronaldo, James Rodriguez and Radamel Falcao, one of super-agent Mendes' clients and has been linked with a big-money move to China in recent weeks.
Jorge Mendes delivered a Real Madrid shirt, signed by Ronaldo, to Chinese Super League club Tianjin Quanjian's owner Shu Yuhiu when they met in China last week. Shu then confirmed his attempted bid for Costa shortly after the meeting.
Tianjin offered Chelsea's leading goalscorer a £30 million per-year package, which reportedly left Costa unsettled - leading to a dispute between him and his coach and ensured he missed Saturday's win over Leicester, though Conte insists the player was injured. However, Costa has been training with the first team squad since Tuesday and is expected to return against Hull City on Sunday.
"I know Jorge Mendes. He's a friend," Conte said at a news conference at Cobham Training Centre. "I never heard Jorge speaking about Diego or about a transfer for Diego. For this reason, I think he has great respect for us.
"Every time Diego has played for Chelsea, he always gives his all for this shirt, for this club. This is the most important thing. I know this and I'm pleased for this.
"For this reason, I'm sure on Sunday that, if Diego starts the game, he'll give his all for this club, the shirt and the fans, and do everything he can to win the game.
"If Diego is not concentrated and he starts the game, the fault is mine because I didn't see it and I made my choice, and it would have been a bad choice.
"It wouldn't be the player's fault, it would be mine because, this week, I didn't see that the player wasn't focused or concentrating and was thinking about other situations."
Conte went on to use the Italian phrase that he "can put my hands in the fire" over Costa's mental state, insisting he has no doubt the striker is ready to play despite the media circus surrounding his future, nor does he believe the fans will jeer him.
“I don't think this situation can happen," he added. "It's not right, it's not right. I repeat: last week, he had this injury, this pain in his back. Now he has come back with us. I'm sure that, together, we have to win against Hull City.
"It's important for me to be focused on everything: on me, on the players, on the fans and on the game, because it's a really important game for us to win. Our fans are really important, always. Because our fans are great.
"They push a lot when we play at home. They push a lot when we play away. And, for us, for me, they are the 12th player on the pitch. I hope to continue in this way, to push a lot our team, my players, in every moment of the game.
"They are a really important part for us to try and win and try and continue to fight for the title."