"Vermögen" und "Einkommen" are the values that you declare in your annual Swiss tax declaration.
"Steuerbares Einkommen" is the annual gross wage of you and your wife minus deductions.
"Steuerbares Vermögen" is what you own in securities, stocks and bonds, real property, cars, heritage, and so on, minus outstanding debts.
Just look at your last tax declaration and transfer the values. Don't cheat

because in CH for a small fee everone can look into others tax data.
By the way: You are not obliged to give any this information to the landlord. He just wants to know if you can afford the appartment. I usually only give the "Einkommen" and leave the "Vermögen" blank (because it's really nobodys business).
Hope I did make sense with my humble Swiss English.