I'd say don't say regret. The negative connotation of that is not as good as... "Hey, I know you have been on hard times and feel guilty for not paying back tha

I'd say don't say regret. The negative connotation of that is not as good as... "Hey, I know you have been on hard times and feel guilty for not paying back that loan. Don't worry about paying...(the rest of your phrasing)