The 28-year-old forward, who is a reported target for Manchester City and Paris St-Germain, is entering the final year of his deal at Emirates Stadium.
"The only thing I can tell you is he is focused," said Wenger.
"My decision is clear - he will stay and he will respect that."
The Frenchman said he would no longer speak publicly about speculation over Sanchez's future, adding: "It is not information anymore, it is suicide.
"He will be here for this season and if we manage to do it for more seasons, we will do it as well."