Do girls worry guys are just nice to get laid?

i really like this, thought i was falling in love. we talked abt hooking up ually, but never did. i broke up with her bc she kept pushing me away and it sucked. i told her i'll always be her friend. im a genuinely very nice person and i like to make others happy bc thats whe kind of person i want to be. we talked yesterday and she told me she really likes me but she was skeptical abt me bc i am "sooo nice" and she didnt know if she cld trust that. is it normal for girls shld be wary of guys? i am trying to just be her friend for a while until i earn her trust.