Traducció - Castellà-Anglès - Quiero decirte que te quiero,que seas...

The target captures the meaning of the source, but could be made closer in style:

"I WILL WAIT FOR YOU ALWAYS" -- this puts the stress on "always", just as on "siempre"

Each "que" should be translated as "that", and the contractions expanded, to keep the formal style of the source: "I want to tell you that ... that ... that ... that in the end ..."

Una, the first "que" is different from the others.
The others are followed by subjunctive as in a wish.
The common verb is "want".
"I want you to take me with you forever"
"I want you to share the rest of your life with mine", etc
I feel using "wish" we render the exact meaning the original has.

Oops! forgot to cc you.

CC: Una Smith

Here is how I would translate the source:

I want to tell you that I love you, that you are brave, from the bottom of my heart I wish that you would take me with you forever, that you would share the rest of your life with mine, that ultimately your feelings change and we are together forever.

After "I wish" the mood is present subjunctive and in the last clause the mood can be expressed without using "would", to convey a lover's hope. Contrast that to the current translation, which conveys a lover's despair. Do you see?

She's not telling him that "he is brave". She is asking him to be brave.