Will marriage to anyone else work after I have had a positive outcome from my first Istekharrah?

If you are doubtful whether your marriage to another person will be successful or not, you should make Istikhaara again.

The positive outcome from your first Istikhaara does not necessarily mean that your present intention to marry another person will not be successful.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai