"Ich werde dafür sorgen."
Translation:I will arrange that.
You would word it differently if you care about something: "Ich werde für es sorgen".
There is no real difference. It just doesn't fit well because "dafür" means "for this [thing]". I wouldn't call something or someone I care about "this thing". It is either a person or maybe an animal, so I would word it more carefully, and "für ihn/sie/es" sounds nicer.
Sorgen can also mean to worry right? How would one say 'I will worry about that'.