Tradução - Português Br-Árabe - Para sua felicidade você venceu!!! ...

Rather than "كن سعيداً بانتصارك" it should be "لقد انتصرت لسعادتك".
desistindo = "الاستسلام" not "اليأس"
Kindly edit your text to convey the accurate meaning.
Thanx.

هدفي كان نقل شعور الشخص من وراء كلماته. فهو يريد ان يقول انك انتصرت فافرح. " افرح يا عم، فانت فزت". اما بالنسبة ل desistindo فهي تعني بالبرتغالية اليأس والاستسلام. واختيار اليأس اقرب الى شعور المتكلم.
http://www.websters-online-dictionary.org/translation/desistir

OK...I get your point.
When I deal with these texts I ask the experts here in the site.
The bridge I was given for this text said: "for your happiness, you won". And I trust our experts since they are native speakers of the language.
So, to me it could possibly mean what you said.
But I was thinking the other way around. That he was fighting to get "happiness" and then he won it!! I hope I haven't strayed from the original.
So I was trying to find something that satisfies all possibilities. We can also try: "لسعادتك انتصرت ".
As for giving up, the reason I thought about "الاستسلام" was due to the concept of winning/losing which indicated an air of "battle".

And thanx for the link

الحقيقة ما افهمه من الجملة هو انه (على فرض ان المتكلم رجل) على علاقة غير مستقرة مع فتاه وانه في نهاية الامر يأس من محاولة اقناعها بخياره، فهنأها بالفوز عليه؟

you are all welcome, I like to use this dictionary. in fact I use only it for most of my work.