"She thinks that she will not succeed even if she tries a lot."
Translation:Cô ấy nghĩ cô ấy sẽ không thành công cho dù cô ấy cố gắng rất nhiều.
Thử = to try something, ex. Try these pants = thử quần này. I like to think of it as trying to test something. Có gắng = to try to do something, ex. Try to become a doctor = có gắng trở thành bác sĩ. I like to think of this as trying with a lot of effort to succeed or accomplish something. Thử đi (try it)! =)