Tru Oil should give it a gloss and make the grain stand out. Another option would be to use Super Glue. Spread on 3 or 4 coats, let dry, sand smooth, and polish.
A lot will depend on what the knife will be used for.
If it gets bloody, then you wash it with dish detergent, you are going to remove most any type of finish.
That is the reason I never tried to put much of a finish on Coco-Bolo and Rose Wood. Also the same for Ironwood and Aftican Blackwood.
I sanded smooth and plished with white rouge and a cloth wheel. When the handle gets looking washed out, and it will if used frequently, just sand lightly and polish again. A coat of wax will prolong the finish, but if you get it wet and wash it, the handle is going to lose the natural oils.
