You can see a trial period as an agreed period in which the employee and employer get to know each other. During this probationary period, both the employee and the employer can immediately terminate the employment contract.
There is no preventive assessment by the UWV or the subdistrict court for dismissal during the probationary period and there is no statutory notice period. So there need not be any of the reasonable grounds for dismissal. Also, your employer does not have to check whether he can redeploy you within the organization. If you become ill during your probationary period, your employer does not have to give you a probationary period extension. If you are fired during your probationary period for this reason, you may be entitled to sickness benefit.
A probationary period is not mandatory. If you choose to take a probationary period, this must be recorded in writing in your employment contract or collective labor agreement.