If she's not interested why cant she just ignore me or say no?

[USMCforlife]

she was in my class last semester but we didn't talk till the last day of class, any how she started to talk to me on face book and she started to text me she looked interested but i always run out of things to talk over im so i pretty sure i bored her to death but she still spoke to me. but i asked her to hang out twice I asked if she wants to hang out first time she said she has a doc appointment and then beach whit her friends second time she was working and told me she will let me know when she's free and said well figure somethin out, i talked to her few times after but we never talked of it and i eft before i ran out of things to talk.i havent talked to her in a month and a half or so but last couple times i talked to her when we were im'ing she just typed random letters then i asked her what she didnt and she said idk but isnt it awesome and the second time did the same and said idk i'm kinda tired and i told he to get some rest and left.
i dont get it why cant she ignoe me or ssay no instead. btw i always run out of stuff to talk no matter who i talk to when i im