有没有语法错误？To be considered for the candidates，you will ideally possess a good knowledge of English，Spanish or French.You'd better have good communication skills and tremendous working enthusiasm.
语法上没有错误，但用词却不恰当。
To be considered for the candidates，you will ideally possess a good knowledge.
用词问题：candidate = 人选 ， will ideally ： 你理所当然会拥有丰富的知识。
To be considered for, 在这里，for 后面应该是职位，不是人选
所以更好的答案会是：
To be considered for the candidate position (职位) ，it is ideal that you are knowledgeable in English, Spanish or French.
或
To be considered for the candidate position, it is ideal that you possess good knowledge in English, Spanish or French.
后半句的意思会变成：你拥有丰富的知识是理想的。
You'd better have good communication skills and tremendous working enthusiasm.
这个句子听起来像个命令， 有点不礼貌。
更好的写法是：
It would be better if you have good communication skills and a passion for working.
Passion 是 热情，热忱。