Nowhere is there even the slightest insinuation that Superman doesn't think Wonder Woman is as good a superhero as he is. Its not about trust, its about emotion. Its two entirely different dynamics and why its an ill comparison. There's nothing to suggest he doesn't trust Diana to get the job done and everything to suggest that its their love for one another that throws a wrench into the logistics behind a team up in a dangerous fight. It suggests that Superman understands that due to his love for her, he's compromised by default. So is she. That's where the possible vulnerability comes into play, not whether or not one trusts the other to get the job done. You're pulling that out of nowhere. You're looking for logic where there is none and comparisons among friends and allies that lack the key component that make this situation incomparable: romantic love. I mean come on man, it would almost support the stereotype that comic fans have never been in a romantic relationship in their entire lives, but I know you're married so you have to get it. The Batman comparison is completely worthless in this scenario. Until a day when the Superman/Batman shippers get their wish, that is.