Tristan Thompson's 'Mystery Blonde' Dinner Date Identified, No Romance

Tristan Thompson was recently seen breaking bread with a lady who isn't Khloe Kardashian -- but there was no funny business, just real estate business ... TMZ has learned.

Sources tell us the mystery blonde Tristan was seen having dinner with in Boston on Sunday is simply his estate manager, who handles his housing affairs ... which she's doing in Beantown, because he's moving there for his new team, the Celtics. They were photographed during their meal, and the Daily Mail pics kicked the rumor mill into high gear.

We're told the estate manager's name is Julia, and we're told she also set up Tristan at his pad in CA. She's looking to do the same for him in Boston.

Our sources say there was nothing romantic about the dinner, and everything about it looked super casual. Julia's wearing a sweater and her hair's up in a bun -- not exactly a date look.

As for Khloe -- who was in California over the weekend while Tristan was away -- we're told she and their daughter, True, are now in Boston with Tristan as he gets established. Mind you, Khloe isn't making a permanent move, as we've previously reported. She plans to make extended visits to Boston, but won't leave L.A. -- so this seems to be one of those trips.