Hey I beleive that this is true factually but I also beleive that it is the WOrd of God so that its implications is NOT only for the Roman believers at that time but for all Christians through all generations.
That if you confess with your mouth, "Jesus is Lord," and believe in your heart that God raised him from the dead, you will be saved. For with the heart one believes and is justified, and with the mouth one confesses and is saved. Romans 10:9-10
The verse states that you must beleive with your HEART and confess with your mouth that Jesus is Lord
This is a two fold condition in order to be saved
That means if you confess with your mouth that He is Lord but don't believe it in your heart than it doesn't work.
Or that if you "believe" in your heart but dont confess with your mouth than it doesn't work either.
I would say that if one really did beleive in his heart
then saying Jesus is Lord and living it would not be an issue. To make it more relevant to the topic of this posting only those Romans who truly believed in their heart would give that confession in front of Caesar.
We should as Christians today take it with the same amount of seriousness!