Zacharias believed he was full of himself for very good reason - because he was awesome. And rich. And talented. And so forth. Really, he could have drafted up a list of all his winning traits, but found that most people didn't care for that (jealousy, he figured).
"Oh was that an attempt at a cutting remark?" he asked with a laugh. "And here I thought Ravenclaws were supposed to be witty. Lost your touch over the years, or just never had it to begin with?" Honestly, he didn't understand why people would want to be married at his age. Well, his mother would have liked it, but he did not want an insufferably dull spouse.
"I'm sure you'll only get to enjoy it briefly, until she realizes she's to good for you." Because... well!