Is there a conflict between persistently supplicating and entreating God to unite the supplicant with the one he loves through lawful means, and the الاستخارة (istikharah) prayer? Is this considered an excess in supplication? And if a girl rejects a proposal after it has been made, is this considered a result of the الاستخارة, or can she be proposed to again?

Istikhara is the delegation of a matter to Allah Almighty, due to His perfect knowledge and wisdom. Its reality is seeking the best choice from Him, Glorified be He. The heart must be emptied of all thoughts and not incline to any matter, because that contradicts delegation. If the heart is attached to something, it contradicts delegation and the sincerity of Istikhara.

No ruling has been reported regarding supplicating for the matter for which Istikhara was performed after the Istikhara. It is permissible to repeat Istikhara.

If marriage does not materialize after Istikhara, one must turn one's heart away from this matter and seek another, while seeking help from trustworthy individuals and making abundant supplications.