Ah, it's been a while, but I'm always glad to help!
"I can't help it, you're so different" -> « J'peux rien y faire, t'es tellement différent. »
Depends on the exact meaning of "I can't help it", thought. There is no perfect equivalent in French. Here, I translated it as "I can do nothing about it".
"Are you sure? How can you know for certain?" -> « T'es sûr? Comment tu peux en être certain? »
"You're a fool, but I love you" -> « T'es un crétin, mais j't'aime »
Or, if you want something a little less polite : « T'es con, mais j'taime. »
"I don't want to feel this way about you, you idiot!" -> « J'veux pas ressentir ça pour toi, imbécile! »
That sentence too had no equivalent. The translation I gave may not fit perfectly in your context.
"Nothing good can come of this" -> « Y'a rien de bon qui peut sortir de ça »
"No matter what happens, I'll be here. I promise" -> « Peut importe c'qui arrive, j'vais être là. Je l'promets. »
Re: Canadian French (Québecois) beta
"I can't help it, you're so different" -> « J'peux rien y faire, t'es tellement différent. »
Depends on the exact meaning of "I can't help it", thought. There is no perfect equivalent in French. Here, I translated it as "I can do nothing about it".
"Are you sure? How can you know for certain?" -> « T'es sûr? Comment tu peux en être certain? »
"You're a fool, but I love you" -> « T'es un crétin, mais j't'aime »
Or, if you want something a little less polite : « T'es con, mais j'taime. »
"I don't want to feel this way about you, you idiot!" -> « J'veux pas ressentir ça pour toi, imbécile! »
That sentence too had no equivalent. The translation I gave may not fit perfectly in your context.
"Nothing good can come of this" -> « Y'a rien de bon qui peut sortir de ça »
"No matter what happens, I'll be here. I promise" -> « Peut importe c'qui arrive, j'vais être là. Je l'promets. »
Hope it helps ~