Build Recurring Income

I don't want my rent going up and down all the time and child support based on my income as it is not the same each month. How do you report income that may be there one week but not the next and so on?

I am planning to transfer the rental income from my house to my wife account for her personal expenses. I will club the rental income in my total income and accordingly paying the tax. Is any interest earned in my wife's account (from the rental income) to be clubbed in my total income?