With Lamine Yamal on track to sign a new contract when he turns 18 this summer, Flick has no doubts about the teen's commitment.
He said, "I have full confidence in him, the player knows it. He loves playing here at Barcelona."
On goalkeeper Wojciech Szczesny's contract talks, Flick continued: "The most important thing, and I spoke to Deco about it, is that the key players stay to guarantee the future of Barcelona.
"The director and I talk a lot and we are on the same wavelength: he knows how to strengthen the team."
Araujo, Fati and Prem duo
Flick also discussed the futures of defender Ronald Araujo and winger Ansu Fati.
On Araujo, he said: "Of course, he signed a renewal. I believe in him 100%. It hasn't been an easy season for him, with (Pau) Cubarsí and Iñigo so established, but I'm sure Araujo will improve a lot next season."
On Fati, Flick said: "It's not my decision; he has a contract and he will decide. When he wants to talk to me, we will talk about it, but it will be up to him to decide."
Flick was also asked about sports director Deco's admission of Barca's interest in Manchester United attacker Marcus Rashford and Liverpool winger Luis Diaz.
He added, "I don't want to talk about players who aren't in my team, but they're both fantastic players and I like them. We'll see what happens."