أنا سعيت في حاجتك
I made efforts on your behalf.
In an affirmative claim, an initial “أنا” can foreground the speaker as the person who acted. If the listener is comparing possible helpers, this position may carry a restrictive implication. It does not, however, always express strict exclusivity on its own.
«أنا سعيت في حاجتك لا غيري»
I sought to help you, not another person.
«أنا سعيت في حاجتك وحدي»
I tried to help you on my own.
The explicit additions sharpen the exclusive reading. The distinction is between prominence through word order and restriction stated with clear limiting expressions.