Why do you think Link chooses Zelda over Ilia in TP?
I feel like this is a loaded question, but I’ll see if I can give my headcanon justice. And I’ll warn you, this is gonna get long.
I want to start this out by saying I don’t think Link just ups and decides ‘Oh Zelda’s prettier so I’m gonna be with her.’ No, I think life happens and situations change and people move on from their first loves.
I do believe that Link did like Ilia when he was younger and before the whole Twilight Invasion. There are obviously very close in the beginning of the game, and I think that if the Twilight Invasion had never occurred and Link did not have to go off and become the Chosen Hero, then yes, he would have married Ilia. But that didn’t happen.
Link’s life was literally turned upside down. He turned into a wolf, learned that the children of Ordon, including Ilia, were kidnapped, and had to deal with a sassy Imp Midna along the way (I totally think Link and Midna were only ever friends btw). So obviously he goes after them and starts saving Hyrule along the way.
But when he finally finds Ilia, she doesn’t remember him. You gotta know that broke his heart. This is where my headcanon comes in. If I remember correctly, it’s kind of a long time in game from when you find Ilia to when you’re told that Ilia’s memory can even be restored. Now it’s hard to judge time in game; it could have been days or weeks or even months before Link knew that Ilia could return to normal. I think that during that time, Link was readying himself for the worst. Cuz what if her memory couldn’t be restored? What if Ilia never remembers him? In doing this, Link subconsciously moves on. Any feelings he had soften and evolve into something different, something not as strong so it doesn’t hurt as much if he loses her forever.
And this keeps going until Link restores Ilia’s memory and realizes that he only sees her as a friend now, an old childhood friend that’s almost like a sister. He rationalizes to himself that he’s not the same anyway, she wouldn’t like him anymore, it doesn’t matter that she’d say she’ll wait, she hasn’t seen what he’s become, wielding a sword against enemies with ease and changing into a wolf when needed.
So he moves on, saves Hyrule, rescues Princess Zelda, destroys Ganondorf, and tries to move on with his life. He escorts the kids and Ilia back to Ordon, but try as he might, I don’t think he’ll be able to go back to his old life in Ordon. He’s been on a nonstop adventure to save Hyrule for months, and suddenly Link’s suppose to settle down again and watch goats. I don’t know about you, but I would go crazy, and I personally think Link would, too.
So what does he do next? This is where we truly dive into the realm of opinions. I headcanon that Link goes back to Castletown and meets with the now Queen Zelda. She understands everything he thought he would have to keep to himself in fear of people thinking he’s crazy or broken from his time during the Twilight Invasion. Of course Zelda wants to knight him for his bravery, but Link attempts to refuse because he’s a sweet humble baby.
Over time the two become close, becoming friends and close confidants when one needs to talk through events of the Twilight Invasion. Eventually, Link takes up a job in the Hyrule Army and becomes Zelda’s personal bodyguard. They fall in love slowly over little actions like Link stopping in the middle of training to feed a stray cat or how Zelda scrunches her nose and plays with her hair while she reads. Soon even Zelda’s council takes notice of their chemistry, and because I headcanon Hyrule as a matriarchal monarchy, it doesn’t matter that Link is a commoner. The council approves of Sir Link and the two are happily married. The End.
Now it’s totally fine if you or anyone think that Link never gives up hope when trying to restore Ilia’s memory, and his love only grows stronger while he saves her and they move back to Ordon together after the game and get married. That’s totally cool, but I like to think that Link and Zelda are soulmates and will (almost) always find their way to each other and fall in love all over again.