Tanya didn't know why, despite all her carefully laid plans and efforts to get closer to Dieter, she ended up failing.
But there's nothing to be done about it, NPCs in the game are inherently unpredictable, their personalities difficult to gauge and quite unique.
Sometimes a single misstep means losing any chance, and there's no way to amend it.
And it's all limited-time quests... even meeting people outside the time limit would be useless despite the effort.
Just like Hill in the Magic Tower, he only befriends those who entered the game earliest... no matter how sincere they act, that Mage who's usually friendly to the Undead Tribe ignores them completely.
Even back in Central City, he used to watch them newcomers with great interest!
Who knows if there's some sort of version restriction, so Hill won't even give them a chance to start a Friendliness quest.
