"After you lived many mountains and valleys, we will be together." This means that after Esperanza get through many series of obsitical that she will face in her life, they will be together.
"For the thousandth time, she wiped the tears that slipped down her face, but this time they were angry tears".This means that she wiped her tear that fell in her face but his time it was a tear of anger. This means that Esperanza is crying because she is angry at Tio Luis
"He wouldn't be grinning like a proud rooster then." This means that Tio Luis would not be laughing when he noticed that Esperanza and her mother left Mexico. Tio Luis wouldn't be so happy.