Verizon prepaid number to straight talk prepaid number?

[Aaron]

Ok so i have a verizon prepaid plan but straight talk is a better deal i want to switch my number over which i know is possible problem being is my girlfriend has a verizon wireless plan no prepaid i want to know if i switch my number over to straight talk if she could still call me for free I will have my verizon number and even if that dont work i heard straight talk is backed up by verizon. this is the only thing keeping me from switching i dont want it to cost her to call me