In light of Raven Dreamer's answer to Why can I sometimes take half of a shops items while the oher half is considered stealing?, how does one get people to like the player-character? In other words, get their disposition higher (towards the player-character) and get them to allow the player-character to take their stuff?
Edit: While rereading kotekzot's answer, I wondered how (easy it is) to affect a relationship negatively.
Edit 2: Then I realized that I was focusing solely on take vs. steal when I could be asking about what else that trustworthiness (as I'll call it instead of relationship) affects. If it is felt that this edit broadens too much; that what trustworthiness affects deserves its own question, this question can be changed back.
How does trustworthiness with NPCs work
the-elder-scrolls-v-skyrim
Best Answer
The only legit way to increase an NPC's disposition toward you is to complete quests for them (or somebody close to them, in a few cases). Not all quests will increase disposition and not all NPCs will have a quest for you.
You can also use
setrelationshiprank player 1in console to befriended the targeted NPC. Read more about console commands.