Kounde is reportedly peeved that Sevilla could not agree a fee with the European Champions.
Chelsea tracked Kounde all summer but could not meet his €80m release clause to price him away from the Estadio Ramon Sanchez Pizjuan.
Kounde has emerged as one of Europe’s brightest defenders since joining Sevilla from Bordeaux in the summer of 2019.
The 22-year-old is currently away on international duty with France but was red carded in their game against Bosnia and Herzegovina on Wednesday.
Rakitic wants Kounde to move on from his disappointment in missing out on Chelsea and give his all for Sevilla.
"Hopefully, on his return from his national team, we can have a moment to be able to talk, sincerely, so that he knows that he has the confidence of us, that we are his second family," Rakitic said in a wide-ranging interview with ELDesmarque.
"It is very important to us. The first thing we need is for him to feel at ease, to be at his best and to know that everything we do, we do together."
"He is a boy, 22 years old, very young," Rakitic added. "He has been here for some spectacular years, that's why he attracts the interest of big clubs with those amounts.
"He has earned that with his game. The most important thing is that he understands that this has already happened.
"Besides being young, he has a lot of experience. He no longer has to teach anything to anyone. He is already a well-rounded player.
"He still has to improve, of course, but he has to continue to enjoy football. It doesn't help him now to be down, sad, or angry. He has to lift his spirits."