Want to prevent action beyond the limit of the people in the pool

I just want a normal relationship, but with a woman's sensitivity, I feel that she wants to go even further.

I have just registered to swim for 3 months, swimming in the morning. I knew someone older than him, at first he just asked for the number to contact normally. I know that person works at a media agency so I asked to buy a child locator watch. I asked to buy but that person insisted on giving me a gift, and after that I was stressed to receive the money. The story did not stop there, the person also texted, said that when I didn't go to swim, I remembered, and sometimes praised me for a nice swimming (I can swim, swim faster than him, but the strength is not equal to him).

In the morning, I and I both swim for about 30-35 minutes, go to the jacuzzi for about 10 minutes and then return. It doesn't matter if you don't take my hand and hold my hand, I have to shake. Then yesterday he waved his leg, seemingly wanting to touch my leg. I managed to get out and leave earlier than expected time. He has a family, the oldest child to work. I don't like that kind of relationship. How do people help me to behave skillfully so as not to offend that person and keep my friendships? To add a little more, during the day I just enlist to go to practice in the morning, then go back to send my children to school, pick them up, cook and let them study at night. Sincere thanks.