Well ... look at what you are doing. You are changing the Tenant name to the value that you are starting with! Which means that the first update - by definition - never makes any changes, and if it did would quite likely mess your DB up, as last names aren't even close to unique. And teh hyphens in your column names don't help at all either...
Probably what you meant to do was this:
UPDATE Tenants SET fname=@fname WHERE [tnant-id] = @tenantId
UPDATE lease SET deposit=@deposit WHERE [tenant-id]=@tenantId
But I'd suggest that you change the column names:
Tenant:
ID,
fName
lName
Age
Lease
ID
deposit
entryDate
departureDate
tenantID
It's more consistent and easier to work with.