A standard answer is the singular they, but that can run into problems. As your question is a translation question, there are wrinkles which that potential duplicate may not address.
The teacher guides their student so they can advance more in their life.
Who do all the pronouns refer to?
I'd choose his or her (referring to a typical but generic individual student) and stick to it. To counter accusations of gender stereotyping, choose the pronoun which doesn't conform to most of your actual students. You might choose the opposite gender for teachers.
The teacher guides his student so she can advance more in her life.
There's no ambiguity there.
If it's a course guide, you might be able to speak directly to the student: use you. Sometimes, especially where the source language is very different from the destination language in a translation, a literal translation isn't possible and it is actually necessary to recast sentences completely. English doesn't have a genderless pronoun in the third person singular except for the [obviously unsuitable] inanimate it and [potentially problematic] singular they (plus some recently coined ones like ze, xe, etc., which remain virtually unused and would probably not be understood), so it's reasonable to avoid the problem altogether. This may well be the best solution.
Your teacher guides you so you can advance more in your life.