From what I understood, Bob had no interest in Sasha as a possible mate. He said "I'll try something right now" and kissed her to see if he could sway her into going with him to search for Maggie, which was always his intention.
Yes, they also discussed this on Talking Dead and Sasha (Sonequa) mentioned that there was nothing there it was more of a way for Bob to entice her to joining him and Sasha used the moment to try to turn the tables and get Bob to stay with her.
Whatever Sasha was trying, it would have worked on me!
But seriously, Bob still left Sasha all by herself to go look for Maggie because she was all by herself. Still seems to me