It is better to ask the colleague’s friend for her number directly.
If this is a girl that you are interested in, you should talk to her and get her number.
If you were to use her colleague to get her number without her permission, it may make her feel awkward when you contact her.
It is better to simply talk to this girl directly and either ask her out or ask her for her number.
She would prefer it if you did it in this way.
It makes you appear assertive and confident.
It also makes her feel like she is a prize that you are intent on pursuing.
She would want to have the confidence in the knowledge that your interest is sincere.
She would want to have a good idea of what your intentions are.
This allows her to have the right frame of mind.
If you were to get her number from a colleague and contact her in that way, she may not be entirely sure of what your intentions are.
This could put her in a very doubtful or insecure frame of mind.
When she has this frame of mind, she will be less willing to open herself up because she isn’t entirely sure of what angle you are coming from.
You don’t want her to feel this kind of confusion.
It would only cause your interaction with her to feel forced, awkward and just plain uncomfortable.
You can easily give her the right impression by being straightforward in getting her number directly from her.
It actually enables you to start communication with a lot more confidence.
If you were to ask her for her number directly and she were to give it to you, you would feel a lot more confident in using it.
She gave it to you after all.
This is the first step towards something more.
She would be expecting you to call her or contact her.
This really helps you make the call with the right mindset and with a lot more confidence.
If you were to get her number through a colleague, you may wait days before using it, if at all.
Being that you got her number indirectly, you may be filled with doubtful questions.
You may worry about how she will react upon hearing from you out of nowhere.
You may worry about when the right time would be to call her.
You may start rehearsing what you would say in order to make her feel more at ease upon hearing from you unexpectedly.
This would only make you sound more unconvincing when you do talk to her.
Hence, getting her number through a colleague will simply make this process even harder for you.
There will be too many conclusions and assumptions being made in your head.
You would create too many scenarios of how you think she may react.
All of this could easily ruin your delivery and cause delay.
To make things a lot easier on yourself, ask her for her number directly.
This also helps to make this process flow in a more natural way.
When you are the one who is asking directly, you are setting a good precedent for how the interaction with this person is going to go.
It gives her a good impression about you and that is a great place to start in your interaction with her.