Is it possible to keep decimals in a value which you save in a variable like .toString?
Yes. It is possible.
Below is the SS for the same. I have taken initialValue as Double.
Mark as solution and like it 
Happy Automation 
Best Regards
Er Pratik Wavhal 
Hi,
Can you just try this method below
Use Assign Activity Doublevariable =“5609.43”
and convert Str(Doublevariable)
Please refer Screenshot below
Regards,
Neelima.