Is a girl obligated to strive to marry someone she loves from another tribe, when her family rejects the marriage due to customs and traditions, or should she submit to her parents' opinion?

If the suitor is a man of religion and good character, your father is not permitted to reject him, due to the saying of the Prophet, peace and blessings be upon him: "If someone whose religion and character you approve comes to you seeking marriage, then marry him. If you do not do so, there will be tribulation on earth and widespread corruption."

You have the right to strive to prevent your father from rejecting this suitor if he is righteous, through several methods: 1. Inform your father of your desire to marry him and that there is no legitimate Islamic justification for his rejection. 2. If that does not work, inform him that he has no right, according to Islamic law, to prevent you from marrying, and that his rejection of him without justification is considered 'adl (unjust prevention of marriage). 3. If that also does not work, take your case to the Sharia courts.

This is assuming that the man is genuinely religious and of good character.

We advise you on the following matters: 1. Seek guidance from Allah (Istikhara) before proceeding with any matter. 2. Know that the guardian (wali) is a condition for the validity of marriage, according to the saying of the Prophet, peace and blessings be upon him: "There is no marriage except with a guardian and two just witnesses. Any marriage other than that is invalid. If they dispute, then the ruler is the guardian of the one who has no guardian." If the guardian prevents marriage unjustly, the matter is referred to the judge. 3. Beware of establishing any relationship or contact with a man who is a stranger to you.