Ensuring you get the correct spelling, in any written language, is paramount. You can get away with slight mispronunciations is most cases, verbally, but on paper you can and will appear not to have an appropriate attention to detail. The consequences can range from implying something you didn’t intend, to not getting a job because you have misspelled a single word on your CV.
Using spell check sometimes just won’t cut it. Some words which sound the same when vocalised are often used incorrectly in the written form. These can be spelled correctly but often misused. There/their/they’re, two/to/too, and your/you’re are all commonly used incorrectly.
You wouldn’t think to submit an essay or letter without proof reading first in your own language. The best spell check you can use when recording text in another language is someone who is a native speaker of the language which you are writing.