Next time, please do format the text. This is really hard to read and even more to pinpoint. If you hadn´t specifically asked me for help here, I would have seen the column on the left and walked away from here.

"Demostrar un amor" sounds a tad strange. It would literally translate as "Empirically proving a real love"
which I don´t think it´s gonna happen XD. You can either "mostrar un amor real" (to show you a true love) or "demostrar amor real" (to give you proof of my true love). But, "demostrar un amor"... that really doesn´t work well.

"When it hurt I ease the pain girl, caress yourframe" -> You can say "tus formas" or "tu cuerpo".

"Persistir" does not mean "to insist", exactly. It means not to disappear or be worn out by time or hardship, and it´s more of a passive act than an active one.

"could straight lace you, not just appearance" -> It does not refer to HER appearance, it refers that he could possess and control him for real, and not just as a pantomime or a show. There´s an expression that would fit, which is "Atar en corto" (to tie with a short leash). It´s commonly used for dogs or pets, but can be applied to humans by extension.

"Te podría atar en corto, y no solo en apariencia" ("solo en apariencia" means "just for show" or "just on first look").

"bagguette diamond" means a diamond of poor quality or a fake. In Spanish, you could say "Diamante de pega" or "Diamante de pacotilla".

"Carro" is an americanism. In european spanish it literally means "cart". As in, drawn by horses. "Coche" would be the modern mechanical equivalent.

"Prefiero enseñarte, es sincero, hacer que tu corazón deshiciera/deshaga" -> If you use "deshacer" you must specify an object for the verb. If you mean to melt or fade of its own is "deshacerse". "Hacer que tu corazón se deshaga".

"Vales/mereces la pena, sólo como mi primera niña" -> "Mereces la pena, eres especial, como mi primer amor".
(As of today, RAE has discontinued the practice of differentiating "Sólo" (alone) and "Solo" (solely) with a stress mark, though most purists- me included- still do it on ocassion).

"I'm that feeling when you can't leave" -> "Soy ese sentimiento que tienes cuando no puedes irte". Remember, "leave" can be either "ir" (move away from) or "dejar" (give up on, abandon or, even, borrow. Yes, I know. It´s crazy).

"Prometo mantenerte lejos de daño" -> "del daño" (de el daño. De+el (article) is shortened as "del")

"soy el valor cuando tienes/tengas miedo" -> Again, fact and probabilty. In this case you can say "Seré el valor cuando tengas miedo" (I will be the breavery when you are afraid), because the future, unlike the present, can admit speculation. But as I said, as a general rule of thumb, stick with either indicative or subjunctive. Mixing them has rather complex rules.

"plant seeds in the soil" -> "Plant seeds" (verb+noun), not "Plant´s seeds" (noun+noun). The spanish verb for "plant" is "plantar."
"Plantar semillas en el suelo"

"por eso te trato real" -> "Real" is an adjective going alongside a verb. You can´t do that. Adjectives go with nouns and adverbs go with verbs. Sadly, "royal" (regally, like a king) does not have an adverbial form in Spanish.
See, "real" in Spanish can mean either "real" (real life, real facts) or "royal", but only in the sense of "real" it does have an adverb, "realmente" (actually). The adverbial form of "royal" is done through paraphrasis.
"Por eso te trato como a una reina", "por eso te trato a cuerpo de rey" (and no, we don´t say "a cuerpo de reina").