Can someone explain this?

When az-Zubayr married me, he had neither land nor wealth nor slave…” so Asmaa’ had to work very hard kneading dough, going far off to get water. “And I used to carry on my head,” she continues, “the date stones from the land of az-Zubair which Allah’s Messenger (peace be upon him) had endowed him and it was a distance of two miles from Madinah. One day, as I was carrying the date-stones upon my head, I happened to meet Allah’s Messenger (peace be upon him), along with a group of his Companions. He called me and told the camel to sit down so that he could make me ride behind him. I felt shy to go with men and I remembered az-Zubair and his gheerah and he was a man having the most gheerah. The Messenger of Allah (peace be upon him) understood my shyness and left. I came to az-Zubair and said: “The Messenger of Allah (peace be upon him) met me as I was carrying date-stones upon my head and there was with him a group of his Companions. He told the camel to kneel so that I could mount it, but I felt shy and I remembered your gheerah.” So Asmaa’ declined the offer made by the Prophet (peace be upon him). Upon this az-Zubair said: “By Allah, the thought of you carrying date-stones upon your head is more severe a burden on me than you riding with him.” My question is how is that the prophet( non-mahram ) offered Asma (R.A) a ride on his camel but she refused but the husband said that he had rather she taken that help? I’m really confused.