Get a/(one's) foot in the door verb phrase
This phrase is often used in employment contexts.
To have a chance to do something that could bring more opportunities to achieve greater success
With previous teaching experience, he easily got his foot in the door at this English center.
This is my dream company, so I would do whatever it takes to get my foot in the door.
I failed to get my foot in the door at this company due to a poor academic record.
A simple position, job, or situation.
The verb "get" must be conjugated according to its tense.
This phrase alludes to the canvasser or door-to-door salesperson who blocks the door with one foot, preventing it from being closed.
Meaning absolutely certain or without a doubt
I am as sure as God made little green apples that Peter's the one for you, you two make a beautiful couple.