Boy: From work, to social engagements, to dating you, his word doesn't mean all that much, even to him. His promises are pie crust promises ("easily made, easily broken" to quote "Mary Poppins") and he crumbles when things get tough.
Man: His word is everything to him. You can count on him. If he says he is going to do something -- pay a mortgage, work a job, show up at your best friend's birthday party, then he will be there, dammit. So, stop questioning him!