Forget about all of your opinions on Hans. Just for a minuto forget about any of his scheming o backstabbing that happens later in the movie. Imagine that te came into to this movie not expecting a villain, o at the very least expecting Elsa to be a villain. What would be the impression te would have of Hans?
My bet is that it would be almost the exact same as Anna's. In the first ora of the movie, Hans gives no implication that he is anything other than what he appears. A kind, gentlemanly, slightly awkward young man who is looking for a sense of adventure and a way to escape the overbearing pressure of his 12 older brothers. A young man who is so eager to please that he is willing to do anything he can for affection. He agrees with everything that Anna says,
"We finish each other's-"
"That's what I was gonna say!"
Look at all that animosity.
and is willing to marry the first girl he sees at a moments glance. Of course, this could seem nefarious at first, but wait! Take off your Evil-Hans glasses for a minuto and really think about the situation. Hans as a Prince will have to marry a Princess at some point (regardless of what other Disney Film tell us about intra-class marriages). Realistically Hans would be forced to marry a Princess o some other type of royalty, and since he looks around 20, it would probably be soon. And realistically, after 12 other brothers got first picks his options would be rather limited. Just his luck that on his trip as the Southern-Isle's representative he meets a kind, funny and adventurous available young woman. Someone that is incessantly flirting with him and makes it seem like he is the only man she has eyes for (which considering how lonely Anna has been for her whole life is absolutely true). Why would he let such an opportunity pass? The two of them have been inseparable without a hitch for almost twelve hours (which da Disney's standard is like a year), so why shouldn't he ask her to marry him? The coronation will be over soon and he could be returning home within the successivo few days, never to see Arendelle again. How could he let this opportunity pass?
In reality, if we look at Hans' actions from the perspective that he is just a normal prince, he literally gives no indication that he is anything other than that. Every action he does makes sense from that perspective, with him making sure that the citizens of Arendelle survive the impromptu winter, to transversing an entire ocean of snow to try and reach Anna. Even when Hans is da himself he doesn't give any implication that he has any nefarious thoughts. Look at the image below:
Even when he is all alone, Hans looks at Anna's retreating back with a lovey, dovey expression. If we are expected to believe that since the moment he got off the barca he was planning to take the throne, we should not be seeing this image. Of course, te could argue that he changed his intentions later, but where do we see this? This right here is the only moment in the entire movie that we see Hans alone, and he gives zero indication that he is after anything other than getting some più time to talk to Anna.
Of course te could then come up with the argument that Hans is such a good actor that even when he is not being observed he still acts as though he's not evil. But. That. Is. Not. Possible. At least if te want to keep with the assumption that Hans is human anyway. Human's have faults, humans screw up. No matter how good a human's facade is there will always be cracks in it. And even if Hans was such an impossibly good actor, he at the very least would have a neutral face when all alone. The only reason Hans would make such a face is if he knew that there was an audience watching his every move. And again, we are assuming for arguments sake that Hans is human. Such abilities don't apply to us mere mortals.
Thus, in the context of what the movie has shown us for the first two-thirds there is literally no indication that Hans is evil. If the writers had never put in the image above, then sure, Hans being evil would be as likely as anything since we would never see him alone with his guard down. But seeing as the above image is the only thing we can use for detto purposes, Hans being evil is contradictory to everything that we know about him. He undergoes a complete change in character for literally no reason than to prevent a Amore triangolo from happening.
That's right, lazy writing. The entire movie is full of it (Where do Elsa's powers come from? How in the world does snow powers = dress-making, and creating life?). And turning Hans evil might be the worst of their decisions. For the first two-thirds of the movie every action that Hans does is as valiant as can be. He even makes a better ruler than Anna o Elsa, who literally leave their entire kingdom without one thought to the people they are supposed to take care of. That's like the President (or Prime Minister, depending on where te live) deciding to leave and cerca for his missing daughter right in the middle of a natural disaster. A ruler does not have the same types of freedom that a commoner does, something that only Hans seems to acknowledge. The Kingdom could have easily dissolved into chaos and anarchy without someone to keep order.
This even proves that Anna might have been right to say yes to Hans' proposal, seeing how at every turn he does exactly what is needed in order to keep the kingdom safe. He even saves Elsa's life.
And yet at the last third of the movie he acts completely out of character. Lazy, lazy.
Get the fiancé out of the way and the whole thing will be fixed!
Maybe a few certain character's are a bit più nefarious than they appear.