Phil had most definitely meant if she liked Luke intimately, but what caught his interest was the fact that liking him that way would have been complicated. How, he wasn't quite sure, but he didn't want to press too much. Mara was young and, in many ways, sheltered. Phil just wanted her to be happy, and for her to find her place on the island.
All thoughts of Luke were lost when she asked if she could trust him. "Of course you can trust me, Mara," Phil replied, turning so that he could look at her more fully. "I'm here for you, whatever you need," he promised. If that meant being a shoulder she could lean on or someone she could go to for advice, Phil was there. Mara had quickly wormed her way into his heart in the best possible way, and he meant every word of what he said to her.