I cannot comment on the translation, only the result. Self-discipline refers to the ability to gain true freedom by controlling yourself. - An ok sentence Some people ,under the belief that only laissez-fairethey can enjoy freedom , seem to ignore its negative impact on life. Needs attention Shift " ," to ", ". Generally don't use under with belief. Have a belief, under an impression. need to change how you use laissez-faire and only. Some people, believing that only under laissez-faire can they enjoy freedom, seem to ignore its negative impact on life. or Some people, of the belief that only with laissez-faire can they enjoy freedom, seem to ignore its negative impact on life. or Some people, of the belief that only laissez-faire can give them freedom to enjoy, seem to ignore its negative impact on life.

Mr Google says for 2 Some people think that only laissez-faire can enjoy freedom, and it seems to ignore the negative impact on life. Which has the same problem, maybe better is Some people think that only under laissez-faire can they enjoy freedom, and it seems to ignore the negative impact on life.