Juntaría is the conditional form of the verb juntar, meaning "to join" or "to bring together". It translates to "I would join".
In this passionate song, Enrique Iglesias uses it to create a powerful and impossible image. He sings, "Por amarte juntaría la lluvia con el fuego" (For loving you, I would join the rain with the fire), expressing that he would do anything, even defy the laws of nature, for the one he loves.
Enrique Iglesias's "Por Amarte" is a full-on, passionate declaration of what it means to be completely in love. He starts by trying to define it, saying that real love isn't something that just "viene y va" (comes and goes), but something that happens only once. He describes it through small, relatable feelings, like when you can't stop thinking about where someone is, or when you see them and get nervous. For him, love is when you hug someone and forget about time, and when you finally realize that person "lo es todo" (is everything).
Then the chorus hits, and things get seriously dramatic! He makes a series of huge, impossible promises to prove his love. He says, "Por amarte robaría una estrella y te la regalaría" (To love you I'd steal a star and give it to you) and that he would cross oceans just for a hug. He even claims he would join rain and fire and give his life for a single kiss. It's incredibly over-the-top and romantic, a perfect example of a classic, heart-on-your-sleeve pop ballad.