Mmm...I guess I don't assume that it's an automatic happily ever after, and Wako might have indeed found it easier to be in love with one or the other instead of both, but given the way the relationships have developed and how things stood at the end it seemed likely that they'll be able to work something out. And since the three of them were explicitly set up against the Tokio/Sora/Ryousuke trio of the previous generation, it certainly felt hopeful that they'll avoid the pain of that kind of relationship trainwreck.