Hey, Negin!
The "very" in this sentence is working as an intensifier. Normally it's used to emphasise the significance or relevance in the context or even to give more intensity to the noun. For example:
The very back of the room
The very beginning of time
In the context, it express the idea that this person is definitely not dedicated enough, then he/she will probably not earn a salary increase.
I hope this helps!