Assalamo alaikum,

I only want to know that what is the meaning of love and Ishq in the view of Quran.

And If someone likes a girl too much(Its happens itself, without any planning and no desire of return) and do not want to lose her(In fact wants to get her), what the person should do?

And in the case of both if (1) a muslim boy likes a muslim girl and (2) a muslim boy likes a non-muslim girl.

And if he can't get her(marry her) there may some harm to the boy even he does not think or plan to harm himself.

With regards,

Your brother in Islam.

1. If she is a muslim ask her if her Parents will let her marry of her own choice or will she get an arranged marriage, the same applies to you. Talk to your parents about it, they may be willing to talk to the girls Parents. If Parents disagree, it could mean No go. Don't try to be boyfriend and girlfriend as it is not allowed in Islam and all hell will break loose in both your homes. Be sure then try to convinse your Parents if you want to marry her.

2. If she is not a muslim, if she is a Christian or Jew. First if your Parents are open to the idea. All parties should meet. If the Parents don't agree it's a No go. Tell her about Islam, see if she is willing to go towards Islam. If Parents are OK then fine if not all hell might break loose.
If she is a Hindu, sikh, atheist, Should be no go. Unless they become muslim. Parents will not be O.K with it. Unless Parents are Super leniant. Then convinse other party of Islam. Don't Play with fire unless you are willing to deal with the consiquences.

What are your Parents Views, If they don't agree to it, they might kick you out of the house.
Don't intentionally Harm yourself. Sometimes not doing anything is the best option