sorry but still the guide doesn't explain it...
It says "After 4 Bardie visits to fitness Betty calls Monica and tells her that she knows about the panties and Monica can ask her to show what she wears today. She can ask Betty about panties near mirrors and in the bedroom. Also, Monica can look at how Bardie checking it too. Also, after that, Monica becomes shaved. " and ok I made it to this point... and next tip is
"When Bardie and Betty became level 5, the next morning, Betty catches Monica again (day, maid clothes) and says that she shouldn’t now wear panties in the house. " bardie is lvl 5 but betty is not, betty is lvl 4 and waiting for the further plot progression same as bardie...