Sinner withdrew from the Barcelona Open quarter-finals last month due to illness and skipped the Madrid Open the following week, but he said he is fully fit for the Italian Open.
Seeded eighth seed in Rome, Sinner reached the quarters last year for the first time and he is aiming to go the distance this time around.
"I have a different mindset now," he told the ATP website on Tuesday. "I'm not scared to say that I can win big, big matches. I'm here, I can do it. But in another way, you have to have the right respect for every single player.
"Every player is so tough. Also emotion-wise, it's sometimes not easy. But if I go in my way, I want to push myself to the limits because I know that, especially there, I can show some very good tennis."
Sinner has been in good form this season, having won his seventh Tour-level title in Montpellier and reaching the finals in Miami and Rotterdam.
The Italian Open runs until May 21, with the French Open Grand Slam beginning in Paris a week later.
