Should I trust something like this? I mean there are many scams right now and I don't want to engage is such. What I want to see is if there are actual people doing betting with you and an actual count of winnings for the said contest that you posted.
It is not about trust, it is all about betting and the OP giving his own tips, and it is not like he is some god that will see the future of what will exactly happen, but he is also simply taking a chance on a team winning over the other which in this case, at least he has been able to make 3 right predictions so far but that does not guarantee anything in the future.
Rather than all these, you must understand it is just gambling and if you cannot have the mind that there is possibility of losing, it is better not to gamble at all.
He is only asking you to join him with his bet if you care, while he gives some tips on his bet, so in that way, I do not see that as any problem, and the choice is all yours.