Rooney was one of England's best performers in their 4-0 victory over Bulgaria on Friday night, however, his place in the team in Basle had come under question after lurid claims in two Sunday newspapers.
The Manchester United striker travelled with the team to Switzerland, however, and Capello said he was confident the player was in the right state of mind to take his place on Tuesdya night.
"Yes he will play. During training he was really good and I spoke with him and he's happy to play," Capello said.
"I know the players when they want to play - that is really important.
"Against Bulgaria he was really, really good on the pitch.
"He will also be in a good situation tomorrow. I hope the performance of Rooney tomorrow will be the same as at Wembley.
"We are focused on the game, not about the private life of the players. We are here to play this game and train very well."
Skipper Steven Gerrard said he expected Rooney to put the off-field matter to one side as England look to begin their qualification campaign with back-to-back wins.
"Yeah he's got an issue off the pitch put I don't think that will stop him from playing well," the midfielder said.
"I spoke with him today at lunchtime and in training and Wayne's been fine. He's looking forward to the game and playing well.
"I think football can do that sometimes (help you focus) if you've got an issue of the field.
"Once the game starts Wayne will be focused on the field and getting the three points.
"Wayne's a big character. You expect big performances from Wayne every time he steps on the pitch. You saw that against Bulgaria. I expect another big performance from Wayne."
Capello denied he had been more lenient with Rooney than with John Terry, whom he removed as captain following allegations about his private life.
"He was captain," the Italian said. "He played in all of the games, I never suspended him."
Although there is a temptation to feel English players have greater difficulty than the mainland European counterparts when it comes to their domestic life, Capello does not believe that is necessarily true.
Quite possibly though, the scrutiny is greater, even if Capello is keen to keep footballing matters and private situations separate.
"It is the world, not only England," he said.
"The same things happen in other countries; French, German, Italian. Sometimes the players ignore the rules of life.
"The players know what they have to do in their private life. But it is their private life."
Clearly, Capello is far more comfortable discussing other matters in connection with Rooney, namely the ease with which he adapted to a new role just in front of the two holding midfielders in the victory over Bulgaria.
Against a Swiss team who claimed their only World Cup win by beating Spain thanks to a blanket defence, the thought of overcoming it without his best player would have been tough for Capello to contemplate, even if there is a body of opinion that the best place for the 24-year-old right now is back in the north-west with his seven-month-old son Kai.
"Rooney will play in the same position because he really liked it," said Capello.
"He gets the ball a lot, he can be free to move around the pitch and he can go from the back towards the goal.
"It is a really important position and you can see how enthusiastic he is. After the game on Friday he was really happy."
Presumably his mood darkened 24 hours later as news of what was being reported leaked out.
It has been suggested the fear of something similar happening during the summer was one of the factors in Rooney's disappointing World Cup.
Not that Capello agrees.
"It was not just Wayne Rooney," he said.
"We arrived in South Africa at the end of the season and all the English players were tired. The level was not the same as it had been before."
However, Rooney's excellent contribution of three direct assists and a major influence in Jermain Defoe's early opener, was a huge factor in a four-goal triumph that would leave them well placed to claim a spot at the finals in Poland and Ukraine if they can follow it up with another success on Tuesday in what is generally regarded as the Three Lions' hardest Group G game.
Michael Dawson's injury means Capello will be forced to select another centre-half to play alongside Phil Jagielka and he will choose from Matthew Upson, Gary Cahill and Joleon Lescott.
While Cahill replaced Dawson at Wembley on Friday, Upson was not even on the bench, a decision explained by the manager.
He said: "All these players are ready to play but you can only choose 18 players.
"You have to decide the first 11 and the players for the bench.
"The most important thing is that players understand what we have to do."
Capello underlined the importance of Tuesday's fixture, saying: "Switzerland are the strongest team in the group.
"This group is very balanced so we need to win every game."