In this song, "I will take you forever" is a poetic way of expressing a lifelong commitment. Here, "take you forever" means to love, hold, and be devoted to this person for an entire lifetime, without ever choosing anyone else. It’s a promise of eternal dedication and loyalty.
This phrasing is less common in everyday language, but in the context of the song, it captures the idea of embracing or committing to someone for as long as life lasts.