This is the sentence that I've come across. I've translated it as:
Once he sees these houses, he thinks that he can definitely buy a house himself.
But I'm always confused by 要. I seems to have several meanings... 'to want to', 'will' and I suspect, in different contexts it has some grammatical meaning.
In this context it seems to mean 'will', though I'd always learnt 要 as meaning 'want to'.
Any guidelines here?