Dic: set out to do something

• When Mary set out to become a writer, she had no idea how difficult it would be to earn a living.
• He has achieved what he set out to do three years ago...
• Salesmen who deliberately set out to defraud customers.
• Are you suggesting that he deliberately set out to sabotage your work?

* * *

■ to begin doing something that is part of a plan.

■ If you set out to do something, you start trying to do it.

■ to start doing something or making plans to do something in order to achieve a particular result.

■ to start doing or working on something in order to achieve a goal.

• When we set out on this project, we knew it would be difficult. [set out on]
• Are you suggesting that he deliberately set out to sabotage your work? [set out to do something]

.... Cambridge Idioms, Cobuild, LDOCE, Macmillan