If you want to lend btc one option is to use bitfinex. The interest is payed daily. You can get a lot of info about them just by google it but if you have any specific questions, shoot me a PM and I'm glad to assist you. I'm using them for over 8 years now. They were hacked at one point but they have compensated all the customers.
It seems that you been a bit confused. OP doesn't want to lend his BTC through any platform or here but to his friends/ private circle.
You are perfectly right, but I'm not confused.
I was just trying to help by providing information regarding an alternative, or after his friend return the loan maybe he want to continue loaning btc, but without the hassle on lending on the forum (scams, collateral, maintaning an active thread, etc... you know what I mean). Also, he can see the rates there so he can have an idee about the interest. If he trust his friend, he might not charge him rates as high as on the forum, because the risk is much lower in his situation.
@OP: To be more on point, it depends on the risk involved and the work involved in providing/maintaining the loan. For examples, on platforms with (almoust) no risk and no work from your part, where the loans are insured, the interest rates varies between 0.001% - 0.01% per day. From here it can only go up, but again, it tepends on your particular situation.
Also, as an advice, there is no loan that is 100% safe, so you should take this into acount.
Good luck.
