The way that most English speakers would say the sentence is, "My friend told me that my English sounds good to her." You can say, "my friend said to me," but "told me" is much more common. You do not need the "is" between "English" and "sounds." If you say, "my English sounds good for her," it sounds like you are saying that she would benefit as a direct result from your English. When you say "my English sounds good to her," you are saying that according to your friend, your english sounds good. My English sounds good to her = My English sounds good, according to my friend (her) My English sounds good for her = My English would be useful to my friend (her)

Not sure the reason, that's just the way that English works! But your friend should have said "your English sounds good to me". ( Not "your English IS sounds good to me) Here are some more examples of correct usage of the phrase "sounds good to me": - Your plan sounds good to me! - The guitar player in the band sounded great to me. - Eric's Japanese speaking does not sound very good to me. You can also use it for how something looks, smells, tastes, feels, or seems. For example: - That's looks good to me! - It looks like an interesting movie to me. - That car looks pretty expensive to me. - The curry smells great to me. - That sofa seems like a great deal to me. I hope this helps! 頑張ってください。

To her is correct. "To" is usually like an opinion. For example, is it interesting to you? For has a different meaning