facebook messenger phone number?

So i have 2 facebook accounts that i use on my phone. 1 for work and 1 personal. I have them set up to 2 different numbers, my work number and personal number. But i synced both accounts to my phone i think. Heres my question. I have someone in my contacts that is a work contact on my personal phone. I contacted them on my work facebook and said they were in my contacts. They arent friends on my facebook, but what number will show up to them, my work number associated with my account, or the number from the phone im using. Im asking due to not wanting my work facebook people to be able to have my personal number. Thanks ahead of time