This preliminary question asks about what N"D is.
The נהמא דכיסופא is a possible explanation for why should we suffer in this world to receive the reward in the afterworld. I tried to verify that:
My father-in-law bought me (us) a new car, he said he loves me. I was very happy and thanked him and felt no shame.
My wife bought me a new GoPro, she said she loves me. I was very happy and thanked her and felt no shame.
If this principle seemingly does not work on Earth, why should we feel any shame to receive free gifts from our Father in Heaven/ב"ז (what is נהמא דכיסופא about)?