I have been doing my best to pray a daily rosary for a friend of mine. That she convert to the Church, that she find lots of good friends,ect. At the end I ask that she like me and go out with me (I have an eminse crush on her). I have worried from time to time that it might be more about what I want than what is best for her, which is what it shoul be. How does one tell when what one does is self-serving or really is for the best of another?
Ask God to give you your respected vocations. That is a better prayer. And examine why you love her. A great document on love is Deus Caritas Est.
The best way of going about it is to state your intentions but always follow them with “whether You grant them or not may Your will be done”. That covers all outcomes.
There are some things God might grant us whether we ask for them or not.
There are other things God might not grant us no matter how much we pray for them.
Then there are still other things in which God might be swayed one way or another depending on our prayers/lack of them for said intention.
God knows ultimately what is best for us. If this girl should ask you out, oh how you should rejoice! If this girl should never ask you out, with the same fervor you should rejoice.