Redknapp reckons selling Modric would send the wrong message about the club, but has no reason to doubt Levy's word.
He told talkSPORT: "It's a happy thing to have a player like Luka Modric, who has suddenly turned into a £50million, £40million player and everyone wants him.
"We're lucky we've got him and we aren't selling him, that's what the chairman says and that's good enough for me.
"The chairman has made a statement. He can't backtrack on that. He means that - I know he means that. Luka's not going.
"Daniel has made that statement - he can't come out and suddenly sell him. Everyone will go, 'What's the use of listening to what he says?' He can't sell him. He's said he's not going to sell him and that's good enough for me.
"Daniel and Joe Lewis own the club. They're not selling Luka - end of story, as far as I'm concerned.
"It's not easy to keep a player who's not happy but the chairman has said we're not going to sell him so we've got to stand by that now. He can't be saying that and then we sell him.
"If we sell Luka Modric where are we going as a football club? We'll have to accept then that we're a middle-of-the-table team that will finish in the top half next season and really that's not what the chairman wants, it's not what I want. It's not, most importantly, what the fans want.
"You've got to keep your best players. I don't see Liverpool wanting to sell Steven Gerrard or Chelsea wanting to sell Frank Lampard, John Terry or any of their top players. Arsenal don't want to sell [Samir] Nasri so you've got to keep your best players if you want to be successful.
"He's such a great player for us we just don't want to lose him. He's a great guy, top-class boy and obviously his head's been turned a little bit by the fact that he's wanted by all these clubs and he could probably go and get a fantastic contract.
"It's difficult but we certainly don't want to lose him. Daniel's made the statement and I'm sure he's determined to stand by what he's said."