A high pressure be seating assembly adapted for liquid sealing against a rigid surface having a connecting conduit. The tube sealing assembly includes a rigid, elongated, tube member having a spherical sector-shaped distal end portion with a radius substantially larger than the radius of the tube member. The tube member further includes a central conduit terminating at an apex of the spherical sector-shaped distal end portion to define an annular rim portion such that a fluid-tight seal can be formed between the central conduit of the tube member and the connecting conduit of the surface. This seal is formed at a contact interface between the rim portion and the surface when a relative axial force is applied therebetween.