How can a ripple wallet trust server? How can a wallet using ripple-lib to interact with the ledger be certain it is seeing the real consensus ledger?  If an attacker has control of the rippled server, or the connection to it, what is to stop them from falsely verifying that funds have been received?

Is it just a matter of trusting server operator + certificate authority + https?  If you are currently connected to a legitimate server is there some data you can save that would confirm that future transactions were verified by the same entity?
One option would be to ask multiple servers: that way you can as sure as you want that. Or you could just run a server—it’s quite simple—and point the wallet to it since, presumably, you wouldn’t lie to yourself.