I assumed that
Asumí que Tom estaba esperando a María.
I assumed Tom was waiting for Maria.
Asumí que haríamos esto todos juntos.
I assumed we would do this all together.
Asumí que Tom y Mary eran marido y mujer.
I assumed that Tom and Mary were husband and wife.
Asumí que tendrían hambre, así que traje unos sándwiches.
I assumed they would be hungry, so I brought some sandwiches.
Asumí que había algo más que debíamos hacer.
I assumed there was something else we needed to do.
I assumed you were in charge.