desmayarse

Con tanto calor, temí que fuera a desmayarse.

With so much heat, I feared she was going to faint.

Se desmayó al ver la sangre.

He fainted at the sight of the blood.

Si no comes nada, te vas a desmayar.

If you do not eat anything, you are going to pass out.

¡Cuidado, que la niña se está desmayando!

Careful, the little girl is fainting!

Se desmayaba con frecuencia por la falta de hierro.

She fainted often because of a lack of iron.