The Alexander Freed novelization confirms that it was Obi-Wan Kenobi.
It took Mon a moment to comprehend. Then she glanced to the closest other councilors and lowered her voice. “Your friend,” she said. “The Jedi.”
Bail nodded again. “He served me well during the Clone Wars and has lived in hiding since the Emperor’s purge.” He appeared to wait for Mon’s verdict, but she had nothing to offer. At last he finished, “Yes, I will send for him.”
Based on what transpired in A New Hope, this was undoubtedly a reference to Obi-Wan
The "trust" thing was about Leia being sent:
A Jedi, returning to fight against the Empire. It seemed an impossible thought, so Mon focused on what was not. “Captain Antilles’s ship is docked with the Profundity for repairs, but it’s nearly ready to go. The extraction should be simple; if it’s not, his skills will be an asset.”
“My assessment as well,” Bail said.
“Whoever makes contact with the Jedi will have a terrible responsibility.” Mon knew who Bail had in mind—it was clear in the tired lines of his face; in the fear of a man who had never previously feared the Emperor’s blackest vengeance. She was reluctant to doubt his decisions, but she needed to be certain. “You’ll need someone you can trust.”
“I would trust her with my life,” he said.