Anhelo is a beautiful, poetic verb that means 'to long for' or 'to yearn for'. It expresses a much deeper and more intense feeling than the common verbs 'querer' (to want) or 'desear' (to wish/desire).
In this song, the singer expresses his profound affection by saying, "Eres lo que yo anhelo" (You are what I long for). He's not just saying he wants her; he's conveying that she is the object of his deepest yearning. This single word elevates the entire sentiment of the line, making it incredibly romantic and heartfelt.
This song is a super sweet and direct declaration of love. The singer is completely head over heels for someone. He's not trying to be cool or mysterious, he just lays it all out there. It starts with that feeling of a crush, where just a look from the other person makes your heart race: "Cuando tú me miras mi corazón palpita" (When you look at me my heart beats fast). He's mesmerized by her, especially her eyes, which he says "brillan tal como perlas" (shine just like pearls).
He also admits to some very real feelings, like jealousy when other people look at her ("Te miran y me encelo"). But he balances this by acknowledging he isn't perfect and promising to give her his all. He's just so grateful to have her, ending the chorus with a simple, powerful line: "Gracias por entrar a mi vida" (Thank you for coming into my life). It’s a song about being so in love that you're determined not to mess it up.