Let us remember, Tuor is the only child of mortal Man who was granted the fate of the Eldar. His pairing with Idril did not sever the family, and he was already sent to Gondolin with a high-doom as a herald for Ulmo himself. I mean, once you speak for a Vala, literally, you’re pretty much in like Flynn. The ‘prerequisite’ of worthiness is fulfilled. Beren and Aragorn had not done their important thing yet. Tuor had.
Tuor and Idril were the first recorded union of mortal Man and Elf, and yes, their life had many sorrows.
On the other hand. Thingol kind of made a mistake. He could not simply give his daughter away to a brief man with no show of worthiness. To give him an errand to prove his merit was fair. But, he erred in judgment and tied his fate, his daughter, and his kingdom to a stupid silmaril by sending Beren on a death-quest.
Elrond was wiser than that, surviving in Middle-earth since the First Age will do that to you, and he accepted that his time in Middle-earth was near its end. The best chance Middle-earth had was to have Sauron fall and to have a worthy king in Gondor. If Arwen was Aragorn’s inspiration, so be it. It was Man’s best chance after the departure of the Elves. Even if it meant losing his daughter forever, he was willing to take that chance to, ya know, save the whole world. Elrond is cool like that.
(Notice how Aragorn is still wearing the ring of Barahir (Bara means ‘fiery’ or ‘eager’ and hir means ‘lord’ - Sindarin) in this image. It probably shouldn’t be there. That ring was given to Arwen as their engagement ring in 2980 T.A.. Although it’s neat to think of the rightful king wearing his First Age bling, a trope used in the film and the game, it’s inaccurate.
That gift is particularly significant because due to Elven custom, an engagement with the Eldar can only be broken if the silver rings are unmade in the place where they were wrought. This ring was forged in Tirion (the high-elf city in Valinor) as it was a ring of Finrod, bearing the emblem of the House of Finarfin. It could not be unmade in Middle-earth. Aragorn would have understood this before giving Arwen the ring. She was his high-elven (Noldo) lady, and although she would choose a mortal life with him, he would follow their customs with her.)
