If Trump doesn't get the nomination, it'll be because the GOPe pulled shenanigans at the convention to stop him. It won't be because he's losing the primary races.
If Trump goes into the convention with 1237 delegates, he should get the nomination. If he goes into it with less than that, then he will have to try to get delegates to switch over to him on subsequent ballots. If he can't and someone else can, that is not "shenanigans" - that is the convention process at work.
So tell me - if Trump goes into the convention with less than a majority of delegates, and assuming the RNC does not make any shady rule changes, if Trump cannot get a majority, will you support the eventual nominee, even if they came into the convention with fewer delegates?