“说句不好听的”意思其实相当于“我接下来要说的话可能会冒犯你，但我不是故意想冒犯你哈”，因此，英文里比较接近的表达有：

　　I don't mean to be rude/disrespectful, but ...;

　　I don't mean to offend you, but ...;

　　或者No offense, but ... ;

　　with all due respect(多用于较正式场合)