Motives, of course, may be mixed; but this only means that a man aims at a variety of goals by means of the same course of action. Similarly a man may have a strong motive or a weak one, an ulterior motive or an ostensible one.
Appearing as such; being such in appearance; professed, supposed (rather than demonstrably true or real).
The ostensible reason for his visit to New York was to see his mother, but the real reason was to get to the Yankees game the next day.