You call her a friend, but then add the ‘dating advice’ tag onto the question. Which is it?
It’s sad, but I eventually just had to just understand that friends are friends for a reason and it’s almost never a good idea to ask one out. If you have feelings for her then you can try to tell her about it, but the chances that she’s going to return those feelings are practically zero.
You shouldn’t ask your friend out because women generally won’t reject guys they consider friends. Instead they’ll say yes but then give you the run around until you catch the hint and move on. It’s disappointing but you just have to accept the reality of the situation.