Beaming smile

Beaming smile
 

¿sonrisa radiante?

My first thought, when I saw 'beaming smile' was sonreír alegremente. :D Sonreír de oreja a oreja.

A gleaming smile sounds more like a sonrisa radiante to me, but as I checked around, it seems that some people equate 'beaming' and 'gleaming' smiles. So, your translation is fine.

Thank you, Rusty! I thought of "sonreir de oreja a oreja" but it seemed "a big grin" to me. A "sonrisa radiante" includes gleaming eyes and a general relaxed fashion. "Felicidad" becomes such an expression: "una sonrisa radiante de felicidad" where "radiante" affects both "sonrisa" and "felicidad".