I think that "ごめんね" is just slightly more informal than "ごめんなさい"... (I think it's just a shortened version of ごめんなさい, but I'm not sure....) ね is used at the end of sentences when someone wants the other person to respond.... It's kind of like "isn't it?".... (Ex. Atsui, desu ne? It's hot, isn't it? (this would probably be a female speaking...) The other person is likely to respond.) It helps conversations continue... よ is an assertive particle.... it emphasizes things. (Atsui, da yo. It's hot! (this speaker is more likely to be male....)) To sum it up, よ is more assertive, while ね is to check the agreement of the listener. Please feel free to send me a message if you have any more questions, or if I've made this explanation confusing! ^-^* ~Megumi