You must have asked this question many times. When you enter Freelancer, you are faced with many translation offers.
But...
Who would be the best option? How to choose?
How can I guarantee the quality of my translation?
1. Who is the best option. Freelancer has thousand of translators offering their services. Always prefer the verified ones (https://www.freelancer.com/verified), that have this badge in their profile: 
Verified freelancers are the best option because they are verified by Freelancer, as they need to confirm their identity and informations through a video call.
The best freelancers in the website (the best 3% ones) in their field are identified with a badge called "Preferred Freelancer". (https://www.freelancer.com/preferred-freelancer-program), and show this in their profiles: 
Preferred Freelancers are the best in their field, which sets them apart from the others.
2. How to choose. Search for freelancers that have those badges and the native ones. For example, if you seek for a translation from ENGLISH >>> PORTUGUESE, always search for Brazilians or Portuguese natives. But be careful, because there are many differences between Portuguese from PORTUGAL and Portuguese from BRAZIL. Several expressions are different and have different meanings.
3. Freelancer also have a guarantee payment system. The amount only will be released after the freelancer delivers the job and you check the results. Never anticipate payments for the projects, and avoid working with freelancers that demand anticipated payments.
Hope I helped you clear your doubts!
See you soon.
Cristiano G.
