If it was correct, he'll pass the funds to the tipster, if not he will return the money to you.
i dont think this 'tipster' would agree to that, theres no need for this guy to agree to using escrow if he really does have insider info and can make a fortune off that information alone. theres no need for this 'tipster' to build trust with op for future deals of any sort, most likely a scammer.
Exactly, if he is not willing to use escrow then that's clear sign that he is not confident and what he wants do is provide a normal tip and if it goes well he'll say it was an inside tip, if it doesn't my guess is that the OP will not hear from tipster again.
The escrow method I proposed would only allow OP to play the bet, escrow will only know the password after the results, so this is the safest way IMO.