Shadow of Destiny is basically all dialogue and a hidden PS2 gem (it's also on PC and PSP). The Metal Gear Solid series has tons of dialogue, Metal Gear Solid 3 might be the best example because of the relationship between Big Boss and The Boss (also lots of dialogue between Big Boss and Eva). Heavenly Sword (developed by Ninja Theory who just released Enslaved) might not be too bad, the main character is female but she doesn't have a male love interest, it's pretty much just dialogue between her and her father and the bad guys, and it's pretty well done. A bunch of JRPGs have lots of male/female dialogue but those games take long to play, and you probably don't have the time.