Hi [imię],
Thank you for your interest and the time you dedicated to applying for the position of [nazwa stanowiska]. We understand that another offer may have been more suitable for you, or your plans may have changed.
We wish you the best of luck in your future job search and finding the job of your dreams.
Best regards,
Dear [imię],
Thank you very much for your interest and the time you have dedicated to applying for the position of [nazwa stanowiska]. We understand that there may have been another offer that better meets your current expectations, or that your career plans may have changed.
We wish you the best of luck in your future job search and success in finding a job that meets all of your expectations and allows you to pursue your professional ambitions.
Best regards,